Edwin H. Pilson, 90, the founder and former president of the old Dupont Iron Works and a Washington real estate broker for many years, died of cancer Tuesday at the Washington Hospital Center.

Mr. Pilson was born in Richmond and grew up there and in Washington. He graduated from the Tome School for Boys in Port Deposit, Md. He was a Washington resident for 75 years.

During World War I, he was an ambulance driver in France with the American Field Service.

He was in the real estate business in Washington until the late 1930s, when he founded the Dupont Iron Works. The firm made ornamental iron, fire escapes and similar products. Mr. Pilson sold the business in the mid-1950s and the site it occupied on 18th Street NW became a parking lot.

He then returned to real estate and was associated with the Sandoz Realty company until his retirement in the early 1970s.

He was a member of the Chevy Chase Club and of the Sons of the Revolution.

His marriage to the former Marjorie Savin ended in divorce.

Survivors include his wife of 54 years, the former Irene Craig, of Washington; two children by his first marriage, Nancy P. Hawkins of Leonia, N.J., and Marjorie Pilson Faust of Ticino, Switzerland; four children by his second marriage, Edwin H. Jr., of Washington, Benjamin F., of Potomac, Anne P. Smyth of Ocean City, Md., and Elizabeth P. Imirie of Chevy Chase; 11 grandchildren, eight great-grandchildren and three great-great -grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society.