Nehemiah M. Cohen, 93, an ordained rabbi who founded Giant Food Inc. and built the company into one of the largest supermarket chains in the United States, died yesterday at Georgetown University Hospital, four days after he was seriously injured in an auto accident.

D.C. police said Mr. Cohen, who had a long history of heart disease, suffered multiple injuries when the car in which he was a passenger crashed into a tree at Albemarle and East Linnean streets near his Northwest Washington home. An autopsy is set for today to determine the cause of death.

Mr. Cohen, one of the pioneers of the supermarket concept in this country, opened his first Giant store on Georgia Avenue NW with a partner, Jac Lehrman, on Feb. 6, 1936. At his death, the company had annual sales of more than $2 billion, 16,000 employes and 132 stores in Maryland, Virginia and the District of Columbia. In terms of sales, the company is the 12th largest food retailer in the United States.

Mr. Cohen stepped down from active management of the company in 1964 and became chairman of the board of directors. In 1977, he was voted the title of honorary chairman and founder.

Born Sept. 10, 1890, in Jerusalem, then a part of the Ottoman Empire, Mr. Cohen attended the Yeshiva as a young man and was ordained a rabbi. He also taught school and developed an interest in farming.

In 1914, he visited England to study the latest developments in agriculture. Shortly after he arrived, World War I broke out, and since England was soon at war with the Ottoman Turks, Mr. Cohen was unable to return home.

He decided to continue his studies in the United States and arrived in this country in 1915.

Mr. Cohen entered the retail food business in Pennsylvania. During the 1920s and 1930s, he owned and operated three small grocery stores in Lancaster with his wife and children, while at the same time keeping a close eye on the first experimental supermarkets that were beginning to open around the country.

The supermarket concept seemed like a good one to Mr. Cohen, who shared his thoughts with Lehrman, a business acquaintance whose family owned a food distributorship in Harrisburg, Pa. In the Depression Mr. Cohen suggested they go into the supermarket business together in Washington, and the Georgia Avenue Giant store opened in 1936.

A shrewd businessman, Mr. Cohen guided Giant Food through a period of steady growth before and during World War II. He was said to have an uncanny storekeeper's instinct and the ability to walk into a store that was not performing up to standard and "smell" the problem where teams of experts and consultants had failed. Mr. Cohen became president of Giant in 1948, and as the population in the Maryland and Virginia suburbs swelled in later years, Giant followed, opening scores of stores in the suburbs.

During that period, however, the spirit of unity and partnership that had characterized the Cohen and Lehrman families gradually dissipated, and by 1964 the company was all but immobilized by internal feuding among the families about how the company should be managed.

One thing they did agree on was a high regard for the company lawyer, Joseph B. Danzansky, who in 1964 was invited to assume the presidency of the company while Mr. Cohen became chairman of the board. Danzansky, who died in 1979, ran the day-to-day operations of Giant Food until 1977, when he was succeeded by Mr. Cohen's son, Israel, who became president and chief executive officer. In 1979, Israel Cohen also became chairman of the board. Another son, Emanuel Cohen, is vice president and treasurer of the company.

A staunch supporter of the state of Israel since its founding in 1948, Mr. Cohen was a regular visitor to his native Jerusalem until the late 1970s. His early rabbinical training remained with him throughout his career, and he was fond of quoting biblical injunctions about the accuracy of a merchant's weights and measures and the need for a businessman to deal fairly and ethically with his customers.

He was the recipient in 1974 of the Shem Tov Award of Washington's Adas Israel Congregation, which is given annually for good citizenship and caring for others.

In 1967, Mr. Cohen received the Management Achievement Award from the Washington chapter of the Society of the Advancement of Management. The citation read, in part, " . . . in 1936 when businesses were failing across the nation, you had the courage and the vision to come to the Washington area with a little tried concept of the time, the self-service supermarket. Your faith in the principle of mass merchandising of foods at a low markup was more than vindicated by the success of your company."

In addition to Israel and Emanuel Cohen, survivors include his wife, Naomi Halperin Cohen, and a daughter, Lillian Cohen Solomon, all of Washington, and five grandchildren.