General of the Army Omar Nelson Bradley, 88, a great commander during World War II whose tactical skill and humanity earned him the nickname of "the GIs' general," died of cardiac arrest last night at St. Luke's-Roosevelt Hospital in New York City.

Gen. Bradley's nickname derived from the fact that while he was field commander of an enormous American army he could achieve spectacular results with relatively few casualties. He was one of only five Army officers to achieve five-star rank during World War II. The others were Generals of the Army Henry Harley Arnold, Dwight Eisenhower, Douglas MacArthur and George C. Marshall.

His last public appearance was Jan. 20, at the inauguration of President Reagan. At that time, the new president greeted him personally and warmly.

Gen. Bradley became the first chairman of the Joint Chiefs of Staff after the armed services were reorganized in 1947. A modest, bespectacled, soft-spoken man, he wore five stars of cloth on his shoulders during his years in the Pentagon, not the traditional metal.

His war service included commands in North Africa and Sicily. He was Eisenhower's field commander during and after the Normandy invasion of Europe on June 6, 1944. In time, he was placed in overall command of four armies made up of 1.3 million men, leading them across France and Belgium and into Germany and playing a vital role in bringing Germany to surrender. He always considered himself one of the infantry.

For some years after he left active service, he was chairman of the Bulova Watch Company. But five-star generals were never placed on the retirement list. Thus, counting his days as a cadet at the U.S. Military Academy at West Point, where he graduated in the class of 1915, he had more than 69 years of military service to his credit.

It was 28 years after Gen. Bradley left West Point that he first saw battle. Those years were spent in stateside training and planning duties, a tour in Hawaii, and attending staff and command schools.

Like a few dozen other officers, including classmate Dwight D. Eisenhower, he was guided and sustained during the years before the war by Gen. Marshall. On Feb. 12, 1941, Marshall jumped him over other officers to the rank of brigadier general and put him to work training troops at Fort Benning, Ga.

The call to battle came in 1943, when Marshall sent him to North Africa as a member of the staff of the U.S. II Corps. He later served as the corps deputy commander under Lt. Gen. George S. Patton. When Patton was named commander of the 7th Army, Bradley took command of the corps.

His service in North Africa and Sicily demonstrated his abilities not only as a soldier but as a man able to get along with allies. He also was discreet and seemingly unassuming. For these reasons, Eisenhower and Marshall chose him to be field commander of the American forces in the Normany invasion.

In his memoirs, Gen. Bradley said the greatest problem was not in getting the troops ashore, although that proved a formidable task, for the invading forces could chose the time and place of attack. The greatest problem, he wrote, was in meeting the enemy's counterthrusts.

Gen. Bradley's 1st Army already was putting to sea when it learned that Omaha Beach was not manned by German trainees, as it had been when the invasion was planned. Instead, Bradley was going up against some of the toughest troops of Field Marshal Erwin Rommel.

Despite the awful difficulties on the beachhead, the invasion succeeded. The port of Cherbourg fell by the end of June, and the beachhead, which by then included the whole Cotentin Peninsula, was secure.

On July 26, the 1st Army broke through the German lines at St. Lo, opening a hole through which Patton would race with his 3rd Army, crossing France and going into Germany. The outcome of the war no longer was in doubt.

On the 25th anniversary of D-Day, Gen. Bradley wrote in an article for The New York Times:

"It was a unified effort by our ground, naval and air forces which decided those hours symbolizing the triumph of the decency that was challenged and tested during World War II. The resoluteness of our fighting men and our allies on the Normandy beaches gives us the opportunity today to build a better America in a better and a more bountiful life . . . nourished by sacrifice, devotion and service."

And he had high praise for the soldiers he commanded on those beaches. "Planning the assault, we originally had counted upon a thin enemy crust of two static divisions between Caen and Cherbourg. Rommel was known to have concentrated his better reserves behind the beach. Among them the crack German 352nd Division which had assembled at St. Lo.

"Had a less experienced division that our 1st Infantry stumbled into this enemy resistance, it might have easily been thrown back in the channel. The choice of the 1st to spearhead the invasion probably saved us Omaha Beach and a catastrophe on the landing."

Heavy fighting continued that summer after the St. Lo breakout. Early in August, the German 7th Army under von Kluge struck across the British front toward U.S. forces at Mortain, seeking to cut across the supply line of Patton's 3rd Army and seal the gap at Avranches.

In doing so von Kluge exposed his right flank to the entire British 21st Army Group, under Field Marshal Sir Bernard Law Montgomery, and his left flank to elements to the U.S. 1st and 3rd armies.

Within a few days von Kluge lost his momentum, and found himself in a narrow pocket with only one small outlet, at Falaise. U.S. forces narrowed the gap to a few miles, then halted to avoid running into the British lines.

Montgomery, a master of the set-piece battle but a man with a distaste for what he once called "disorderly actions," moved so slowly upon Falaise that much of von Kluge's army got away, squeezed back out of the gap "like toothpaste from a tube," as Eisenhower later described it.

About 70,000 Germans were killed or captured in the action, the best parts of 19 divisions, but about 40,000 elite armored troops escaped with much of their equipment to harass and delay Allied forces all the way to Berlin.

Montgomery called it a great victory and claimed the lion's share of the credit. Gen. Bradley said nothing; there was a war on, and he had enough enemies. It was only 20 years later, after repeated provocations from Montgomery that Gen. Bradley delivered himself of the opinion that the British failed at Falaise "because Monty was so darned scared."

This reticence was Gen. Bradley's lifelong characteristic, and it was the despair of war correspondents. He was called "the GIs' general," because he was approachable and spent as much time as possible with the men in the line, and it was said his troops loved him.

If any correspondent could make a general who sends men to die in battle seem lovable, it was Ernie Pyle. Here's Pyle giving Gen. Bradley his best shot, in the summer of '43:

"Gen. Bradley is a hard man to write about, in a way, because he is so normal. He has no idiosyncracies, no superstitutions, no hobbies. He doesn't collect seashells. He doesn't read Schopenhauer. There is nothing spectacular about him."

Pyle casting his homespun net, seized out a couple of anecdotes. Gen. Bradley always added "if you please" when he asked an Army operator to make a telephone connections, and when he was at Fort Benning, Gen. Bradley took home, for canning, wild berries, plums, grapes and figs that he saw while hiking and didn't want wasted.

And it is said that on the beach at Normandy he gave his fleece-lined jacket to a corporal who had lost his own, saying, "I can get another one easier than you." The incident, if it happened, was not mentioned in "A Soldier's Story," the unassuming but far from humble, best-selling memoir Gen. Bradley published in 1951.

He summed up Korea as "frankly, a great military disaster." Beyond the question of civilian control of the military, he said, MacArthur's desire to widen the war threatened to bring on World War III.

The MacArthur crisis was his first serious encounter with high-level politics. It left a bad taste in his mouth as did the whole "Korean Conflict," of which he said: "It was the wrong war, in the wrong place, at the wrong time, with the wrong enemy."

In 1967, he said of Vietnam: "I think this is the right war with the right enemy." Asked about the the danger of the renewed threat of war with the People's Republic of China, he replied, "I feel we have to take this risk."

In that year -- along with former presidents Truman and Eisenhower -- he subscribed to the statement, "We strongly support our commitment in Vietnam and the policy of noncompromising, although limited, resistence to agression. . .

"We are opposd to surrender, however, camouflaged. . . . We favor a sensible road between capitulation and the indiscriminate use of raw power. . . "

In September 1967, he wanted to invite North Vietnamese President Ho Chi Minh to tour South Vietnam to view U.S. military strength there. This, Gen. Bradley said, would make Ho realize "the futility to continuing the war."

While Gen. Bradley described himself as a conservative, he was among the first to speak out against the post-World War II reactionary wave that culminated in the McCarthy era. In 1948, he said Americans "who emulate totalitarian governments in the curtailment of liberties to our minority groups" display "a tragic disparity between what we practice and what we preach. . .

"We cannot fight Communism only with anti-Communism. To be anti-Communist we must be consistently and courageously prodemocratic in our preachments and practices throughout the world.

"We must stand ready to champion human rights whenever they come in conflict with property, privilege or prejudice -- as readily as we would defend those rights from aggression and oppression."

But Gen. Bradley was caught napping by President Truman's July 1948 order desegregating the services. "The Army is not out to make any social reforms," he said. "The Army will put men of different races in different companies. It will change that policy when the nation as a whole changes it." The Army in fact desegretated, under Gen. Bradley's direction.

Because of such embarrassments Gen. Bradley avoided public statements when he could. But one statement that has been often quoted he never regretted. It was made at Longmead, Mass., at the reburial of Cpl. Edward K. Wilkin, a Medal of Honor winner killed in action on April 18, 1945, in Germany. This, Gen. Bradley said, was how Cpl. Wilkin and a legion of others came to die:

"Secure in distant and peaceful towns like this, clinging to comforts, refusing risks, seeking safety in refuge and refuge in words, we recanted power and conscience to side with those who sought peace at any price. Too late we discovered the price was too high; and to keep our freedom we paid in the bodies of our young sons."

Gen. Bradley came from such a town, Clark, Mo., where he was born Feb. 12, 1893. He had a grandfather on each side in the Civil War. The name Omar, which he pronounced Ohmer, was given to distinguish him from all the other Bradleys around, and was lifted from the local newspaper editor. His middle name of Nelson came from the family doctor.

Mary Elizabeth Quayle, who became Mrs. Bradley in 1916, gave him a daughter, Elizabeth Bradley Beukema Dorsey, now of Washington. Mrs. bradley died of leukemia Sept. 12, 1966. In 1967 Gen. Bradley, then 73, married Esther Dora Buhler, 44, a Hollywood writer who was working on a screenplay of his life.

They have lived in the ome Gen. Bradley built on the crest of a hill high above Sunset Boulevard in Los Angeles. He commuted from there to New York where he had served since 1953 as an executive and then chairman of the board of the Bulova Watch Co., employing the organizational skills he developed a sa soldier and honed as head of the Veterans Administration after the war.

He accepted the latter post reluctantly, at Truman's urging. The president once siad, in commiseration, "The losing generals got a rest, but poor Bradley had to come home to take care of the wounded."

Of ordering men to their deaths, he said on a European battlefield, "It's really harder on some of the newer officers than it is on me. For although I don't like it, after all I've spent 30 years preparing a frame of mind for accepting such a thing."

He never got over the sense of wonder that stayed with him as he shot from a lieutenant colonel overtime in grade to the command of a division, then a corps, an army and an army group.

On the morning of VE day, sitting in his billet in Germany, he wrote, "A canvas mapcase lay under my helmet with its four silver stars. Only five years before, in civilian clothes, I had ridden a bus down Connecticut Avenue to my desk in the old Munitions Building."

Gen. Bradley was administrator of Veterans Affairs from 1945 to 1947, when he relinquished that post to become Army chief of staff and, in 1951, the first chairman of the joint chiefs.

He was later chairman of the military committee for the North Atlantic Treaty Organization. He continued to serve as U.S. representative with the NATO military group until his retirement.

Gen. Bradley went off active duty -- five-stars don't retire -- in 1953 after 43 years of active service and, at the age of 65, became an executive of Bulova and in 1958 its chairman.