Henrietta Winning Foster, 74, a retired director of the Chevy Chase playground in Washington, died of cancer Monday at Sibley Memorial Hospital.

Mrs. Foster was a D.C. playground director for 20 years and director of the Chevy Chase playground for 13 years before she retired in 1968.

She was born in Wellington, New Zealand, where she met and married Julian Barringer Foster, a Foreign Service officer who opened this country's first embassy in New Zealand in the mid-1920s.

Mrs. Foster accompanied her husband to diplomatic posts in Washington, Denmark and Singapore before moving to Washington in 1942. Her husband died in 1944.

She belonged to All Saints Episcopal Church in Chevy Chase and in Rehoboth Beach, where she also maintained a home. She was a member of the Southern Cross Club and DACOR, the organization for retired Foreign Service officers and their wives.

Survivors include three daughters, Juliette Hinton of Mobile, Ala., Margaret Isaminger of Oswego, N.Y., and Beverley F. Monroe of Washington; a sister, Jean Murray, and two brothers, William and James Leckie, all of Wellington, New Zealand, and eight grandchildren.

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