Joshua I. Miller, 64, a retired mortgage banker in the Washington area who was active in professional organizations, died of cerebrovascular disease Jan. 9 in his home in Bethesda.

From the mid-1950s to 1968, Mr. Miller worked for the Carey Winston Co., where he rose to be executive vice president. He then joined Walker & Dunlop as vice president and general manager of the loan department. In 1971, he founded the Joshua I. Miller Mortgage Co. in Bethesda. He retired about two years ago for reasons of health.

In the 1960s, Mr. Miller was a founding director of the Old Line National Bank in Rockville. Old Line later merged with the University National Bank of Maryland and Mr. Miller was elected to that bank's board of directors in 1970.

He was president of the Mortgage Bankers Association of Metropolitan Washington in 1967 and was a member of the National and Washington boards of realtors.

Mr. Miller was a native of Washington. He was a graduate of Sidwell Friends School and the University of Maryland. He served with the Army in Europe during World War II.

He was a member of the Terrapin, University and Columbia Country clubs and the National Presbyterian Church.

Survivors include his wife, Janet, of Bethesda; a daughter, Kristine Miller McGehee of Washington; a son, Kent of New York City, and three sisters, Suzanne Spillman of University Park, Eunice Ellis of Philadelphia and Jean Sharp of Albuquerque, N.M.