Ernestine Block Grigsby, 88, a former vice president of the Prince George's County School Board and former government employe who was active in volunteer organizations, died Feb. 1 at a hospital in Boulder, Colo. She had a heart ailment.

Mrs. Grigsby, who was a resident of Boulder, lived in the Washington area for 43 years before returning to her native Colorado in 1977. Before moving to the Washington area in 1934, she had graduated from the University of Colorado and taught in the Denver public schools.

From 1936 to 1938, she was community organization director of the National Youth Administration, then was an administrative assistant with the Agriculture Department, the old War Production Board and the Federal Security Agency before retiring in 1944.

She served on the Prince George's School Board from 1956 to 1962, and was its vice president for the last three of those years. She was secretary of the Woman's National Democratic Club from 1938 to 1940, and had served on an advisory committee to Prince George's Community College.

Mrs. Grigsby was a past national president of the Delta Delta Delta Sorority and past chairman of the National Pan-Helenic Conference. She was a judge at the 1960 Miss America Pageant.

Her husband, Jospeh D. Grigsby, died in 1976. Her survivors include a son, Robert J., of Longmont, Colo.; a daughter, Jane G. Sencenbaugh of Colorado Springs; a sister, Josephine Miles of Denver; seven grandchildren and eight great-grandchildren.