Nguyen Be, 51, a former colonel in the Army of the Republic of Vietnam and the former director of the Revolutionary Development Program school at Vungtau, Vietnam, died of cancer Sept. 5 at Fairfax Hospital.

Col. Be, who lived in Arlington, left South Vietnam in 1975 when the communists took over the whole country. He settled in the Washington area at that time and had been employed since then in the Vietnamese Task Force in the Department of Health and Human Services and its predecessor, the Department of Health, Education and Welfare.

A native of Hue, vietnam, Col. Be fought against the French with the forces of Ho Chi Minh, the communist leader, until 1951. He then joined the government forces under former Emperor Bao Dai. He remained on the republican side of the Vietnamese conflict.

In 1966, he helped organize the Revolutionary Development Program, which was sponsored by the U.S. government. The members of the RDP, also called the "black pajama program" because its members wore the black pajama-like clothes common in Vietnamese villages, were supposed to counter the Vietcong by identifying with the aspirations of the villagers.

Col. Be and his RD program were among the efforts most ardently promoted and praised by the U.S. government during the war. Its training school at Vungtau frequently was visited by prominent Americans and other foreigners.

Col. Be was in Saigon when the city fell to the communists. His wife and six of his seven children were in Vungtau. The colonel is said to have believed his family could leave the country when he did. They are still in Vietnam.

In addition to his wife and childdren in Vietnam, Col. Be is survived by a son, Nguyen Le Minh, who was a student in the United States at the time of the communist takeover and who now is a resident of New York City.