Joseph Hirshhorn, 82, the immigrant, self-made uranium tycoon and art collector who donated $50 million in paintings and sculpture to establish the museum on the Mall named for him, died last night after suffering a heart attack at his Northwest Washington home.

The intensely dynamic 5-foot-4-inch entrepreneur and art patron collapsed about 11 p.m. as he and his wife were returning to their home on Bancroft Place after an evening out. He was taken to George Washington University Hospital where he died at one minute before midnight.

Born in Latvia the 12th of 13 children, Mr. Hirshhorn came to America with his widowed mother when he was 6, settled in an immigrant section of Brooklyn, and surmounted a dismal boyhood and grinding poverty to make a great fortune, rub elbows with the educated and cultured and see a museum named for him dedicated by a president of the United States.

The immigrant who once "stayed alive on garbage" became one of those whose lives, or at least whose legend, embodied and even outstripped the American promise of unbounded opportunity and unrestricted wealth for a man of energy, intelligence and ambition.

Dropping out of school at the age of 12, Mr. Hirshhorn started out by selling newspapers, moved to Wall Street, made his first million before he was 30 and finally, through shrewd and secret maneuver, acquired vast and fabulously valuable Canadian uranium mines.

Meanwhile, much of his growing fortune was spent on the art collection that helped make the Hirshhorn Museum a dazzling success from the day it opened in 1974. By 1976, the collection built on Mr. Hirshhorn's artistic and acquisitive instincts was drawing 1.5 million visitors a year to the gleaming circular building on the Mall, outstripping the Museum of Modern Art in New York to become the fourth most popular art museum in the United States.

Whatever the triumphs and satisfactions the success of the museum may have given Mr. Hirshhorn, they were not earned without frustration and heartache.

His insistence that the building be named after him was not viewed with universal admiration and approbation. Indeed, it produced a flood of protest.

Mr. Hirshhorn's curator, Abram Lerner, recalled telling Mr. Hirshhorn: "Joe, it will go easier for you if you don't insist upon having your name on the museum.

"And he knew that," Lerner added. "But he said, 'Dammit, this was my life's work and I want my name on it.'"

As it turned out, he got his way, but the controversy was sufficiently bitter that for a time afterward, Mr. Hirshhorn was separated entirely from the museum and its activities. Finally, in December 1977, it was decided by the trustees that the man who had formed the museum's collection should become one of them.

Joseph H. Hirshhorn was born in Mitau, Latvia, on Aug. 11, 1899, and after the death of his merchant father, came with his family to the Williamsburg section of Brooklyn, where his mother worked in a sweatshop and Mr. Hirshhorn was expected from childhood to fend for himself.

"Poverty has a bitter taste," Mr. Hirshhorn once told an interviewer."I swore I would never know it again."

Those who searched his childhood for signs of the man he would become noted that at least one element of relief in the harsh landscape of his boyhood was provided by the annual Christmas gift calendars sent out by the Prudential Life Insurance Co.

Above his bed, Mr. Hirshhorn pinned their reproductions of animal paintings by Sir Edwin Landseer and of ladies of high fashion by Adolphe Bouguereau. These were his first introduction to the graphic arts.

Meanwhile, Mr. Hirshhorn's introduction to economic reality took him from selling newspapers to a job as an office boy on the Curb Market, later to become the American Stock Exchange. With $255 saved from a job charting stocks, he established himself in his teens as a broker, making $168,000 in his first year.

Two months before the great crash of 1929, having amassed $4 million, Mr. Hirshhorn suddenly pulled out of the stock market, demonstrating either luck, wisdom or some combination of the two that he appeared never to lack thereafter.

Canada became his next arena of financial maneuver. "My Name is Opportunity and I am Paging Canada," read the grandiloquent advertisement he placed in a Toronto mining newspaper in 1933. Three years later, having obtained substantial holdings in what appeared to be unrewarding mines, he found gold within a few yards of an old shaft.

In the late 1940s, after the dawn of the nuclear age, Mr. Hirshhorn became interested in uranium. His financial support of the unconventional theories of one Canadian geologist led to successful drilling tests and prompted an elaborate strategem to stake claims quietly before news could leak out.

According to art critic Aline Saarinen's book,"The Proud Possessors," "Scores of mining licenses were taken out in deceptively scattered points; fishing and hunting licenses were obtained to allay . . . suspicions . . . ; dozens of stakers in pontoon planes were dispatched to unidentifiable parts of the . . . land to follow the siren tick of Geiger counters."

By July of 1953, Mr. Hirshhorn had acquired 1,400 claims covering 56,000 acres; one of his mines was said to be capable of producing more uranium than all of the mines in the United States. Three years later, Mr. Hirshhorn obtained $50,000,000, mostly in stock for his Canadian properties, and in 1960 he sold his uranium interests and began reducing his business involvements.

Active and decisive in business, where he was known as a hunter of bargains, he showed similar traits as a collector, stunning dealers with the speed and size of his purchases. Repeatedly he was quoted as playing variations on one basic theme: "Why don't you throw this one in for the same price?"

Early in his career he bought on a dealer's advice and regretted it. Thereafter he relied on his own taste. "It's got to get me here," he would say as he thumped his chest.

To a dealer who advised on the investment value of paintings he retorted: "Don't tell me how to make money. I don't collect art to make money. I do it because I love art."

Although some suspected that much may have been hidden behind the personality the world was shown, Mr. Hirshhorn seemed all energy, instinct and confidence. Art critics described his "feel" for art as almost infallible. One said "he actually feels a moral obligation to understand what he buys."

His years of art buying culminated on that clear cold January day in 1969 when Mr. Hirshhorn stood next to President Lyndon Johnson at the groundbreaking for his museum and said: "It was an honor to give my art collection to the people of the United States." Five years later, when the museum finally opened, he said "I repeat, it was an honor for me to give my art collection to the people of the United States." CAPTION: Picture, Joseph Hirshhorn...donated $50 million collection