D. Joseph Reardon, 81, founder and operator of D. Joseph Reardon Associates, a kitchen supply firm in Gaithersburg, died of cancer Tuesday at Montgomery General Hospital in Olney.

Mr. Reardon came to the Washington area in the mid-1930s and worked as a salesman of building supplies. He founded his own firm in 1943 and remained active in it until his death.

He was born in Portsmouth, Va., attended Mount Saint Mary's Seminary in Emmitsburg, Md., and became a civil engineer for the old Seaboard Airline railroad although he had lost the sight of one eye in a boyhood accident. He worked in several areas of the South, but had to give up his railroad work when the sight of his remaining eye began to fail.

Mr. Reardon was a charter member of the Silver Spring Elks Lodge, a member of the Silver Spring Board of Trade, a member of the Silver Spring Rotary Club, and a past president of the Issac Walton League in Montgomery County. He also was a member of the Holy Name Society of St. Catherine Laboure Catholic Church in Wheaton.

Survivors include his wife, Lucielle B., of the home in Rossmoor Leisure World in Silver Spring; a daughter, Anne Parker, of Alpharetta, Ga.; two sons, Daniel J. Jr., of Marietta, Ga., and Dennis J. Jr., of Marietta, Ga., and Dennis J., of Boston; six grandchildren, and one great-granddaughter.

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