William Saroyan, 72, an author and playwright who wrote about a vast assortment of engaging and unlikely characters who shared his own belief that life and love are one and the same, died yesterday at the Veterans Administration Hospital in Fresno, Calif. He had cancer.

The son of Armenian immigrants, Mr. Saroyan was born in Fresno. He spent some time in an orphanage after his father died, was reunited with his mother and brothers and sisters in Fresno, worked in the vineyards of an uncle, listened to the folk tales of his family, learned about the difficulty of immigrants in trying to maintain their values and customs in a new land, met itinerant farm workers, laborers, and a wide variety of people who were down on their luck and -- worst of all -- isolated and lonely. From these he fashioned a world of fantasy and parable in which the bleak reality of today never dimmed the promise of tomorrow.

Having decided at the age of 14 that he was a writer, Mr. Saroyan transferred from Longfellow Junior High in Fresno to Technical High so that he could learn typing. In 1934, at the age of 26, he had his first success with the publication of "The Daring Young Man on the Flying Trapeze," a short story about a struggling young writer who dies of starvation. This was published in book form together with 26 other short stories, each of which he reportedly wrote in a single day. w

In six days of 1939, Mr. Saroyan turned out "The Time of Your Life," a play which won both the Pulitzer Prize for Drama and the Drama Critics Circle award. The author turned down the Pulitzer because he said he resented "wealth patronizing art." The play was made into a 1948 movie starring James Cagney.

"The Time of Your Life," his most enduring work for the theater, has all the elements of warmth, hope and understanding that are associated with Mr. Saroyan's unabashed romanticism. It is set in a bar called "Nick's" on the Embarcadero in San Francisco. The only one of the characters who can be sure of where his or her next meal is coming from is "Joe," who has money and who has been sitting around "Nick's" for a month.

Other characters include "Kitty Duval," a hooker who would like to be in vaudeville, a struggling young musician, "Kit Carson," who is out of a wild West show and full of tall stories about a female midget, an errand boy whom "Joe" keeps busy buying toys and candy just for the heck of it, "Blick," a vice squad detective, and "The Arab." From time to time, "The Arab" bestirs himself to say, "No foundation, all the way down the line." "Blick" is the heavy, for he holds other people in contempt -- the ultimate sin for Mr. Saroyan. The story tells how "Joe" helps make the dreams of his fellow drinkers come true.

In the opinion of the critic Edmund Wilson, the great strength of the play is in the atmosphere that Mr. Saroyan has brought to life.

"Saroyan takes you to the bar, and he creates for you there a world which is the way the world would be if it conformed to the feeling instilled by drinks. In a word, he achieves the feat of making and keeping us boozy without the use of alcohol and purely by the action of art."

In short, it all comes out the way it would if the world were the way Mr. Saroyan, who said, "In the time of your life, live," thought it should be.

In the introduction to an edition of three of his plays, "The Time of Your Life," "My Heart's in the Highlands" and "Love's Old Sweet Song," the writer explained why he wrote the way he did.

"I read 'Lady Windermere's Fan' when I was 14," he said, "and the same day wrote a very good play in imitation of that worldly and brilliant style. It didn't seem right for me, however, I had that much sense. But it was very easy to do. I had all the wit for it, but the environment was wrong.

"My World was a world of plain and poor people, broken-down houses, casualness, good health, poverty, and uproarious laughter, rather than a world of complex and wealthy people, magnificent houses, cultivated ease, pretended health, and sophisticated and discreet laughter. I knew it would not do for me to write plays after the manner of Oscar Wilde."

Nor did his optimism and the sense of his roots desert him in later life. In "The Bicycle Rider in Beverly Hills," which was published in 1952 and which is one of the numerous autobiographical sketches he produced, Mr. Saroyan said of his growing up:

"Every day was an adventure, a new chance to draw nearer to that great state of health which approximates immortality, where the senses are so finely alive."

And in an interview published in The New York Times in 1972, Mr. Saroyan said it had become clear to him that he was on "the downward part of my path through life. . . . After I got over the initial shock of being subject to the same laws as everybody else, I learned to appreciate the changes that came over my life. . . . Now I live out of what you might call intelligence rather than sensibility. Intelligence makes for integration and I need that now. You could say I'm the same as always, but different."

Mr. Saroyan's output was prodigious. It is estimated that he wrote more than 400 short stories. Some he published were in a story-cycle form and one of the best of these was "My Name Is Aram," which appeared in 1940. It tells of a boy growing up in the Armenian community of Fresno. Among his novels was "The Human Comedy." He also wrote a film script from the book. The film version, which starred Mickey Rooney, appeared in 1943. He wrote song lyrics. His most spectacular sortie into that genre was his collaboration in 1936 with his cousin, Ross Bagdasarian, on "Come On-a My House," which became a smash hit when Rosemary Clooney made a record of it in 1951.

Having grown up in Fresno -- Mr. Saroyan once said, "I met the human race in Fresno. I found it a fascinating race. I found it complicated, paradoxical and contradictory" -- he became a Western Union messenger. He went to San Francisco as a branch manager for that company and it was in San Francisco that he gained success in his chosen career.

He sent "The Daring Young Man on the Flying Trapeze" to Story magazine, which paid him $15 for it. He followed this with dozens of other stories, all of them written at break-neck speed and none of which he bothered to rewrite. Critics greeted him as a fresh if undisciplined new talent. A more recent assessment is that of Gregory Grigson in "The Concise Encyclopedia of Modern World Literature" (1966).

Grigson said, "Anyone who writes and publishes with Saroyan's uncritical enthusiasm buries his diamonds in rubbish. The diamonds are worth searching for."

During World War II, Mr. Saroyan went into the Army as a private, vowing that he would write the definitive novel of the conflict. Most of his service was with a Signal Corps film unit in London. When he returned to civilian life, he published a novel, "The Adventures of Wesley Jackson," which has been called "the first anti-war novel of World War II."

Despite his success with the public -- it has been estimated that he earned $2 million from his writing -- Mr. Saroyan was plagued with financial problems. He apparently was a compulsive gambler for much of his life and it is said that his losses ran into the tens of thousands. He also had problems with the Internal Revenue Service, for he could not pay his taxes.

In 1959, he moved to France, hoping to live in a tax-free status and thereby enable himself to make enough to pay his debts to the U.S. government. He later bought a house in Fresno and in recent years had divided his time between Paris and California.

In 1943, Mr. Saroyan married Carol Marcus, a beautiful young heiress. They had two children, Aram and Lucy, and were divorced in 1949. Two years later, they were married again and then divorced again.

Mr. Saroyan was rotund, about 5 feet 8 inches tall. He wore a walrus mustache and had the manner of an indulgent uncle who thought he was somehow different and special. He was hospitalized a month before his death. With the onset of his final illness, he said in an interview with the Associated Press: "Everybody has got to die, but I have always believed an exception would be made in my case. Now what?"