Charles Merile Chafin, 78, a decorated veteran of World War I and a retired Department of Labor official, died of pneumonia Wednesday at Suburban Hospital in Bethesda.

Mr. Chafin was born in Williamson, W. Va. At the age of 15, he ran away from military school to enlist in the Army. He served in France and participated in several major operations, including the second battle of the Marne, the Meuse-Argonne Allied offensive and the battle of Saint Mihiel. His awards included the Distinguished Service Cross, the Purple Heart and the Croix de Guerre from France.

He also served in the Navy during World War II, as a chief petty officer stationed in Iceland.

Mr. Chafin attended Emory and Henry College in Virginia. He joined the Labor Department in the late 1920s and worked primarily with migrant and seasonal farmworkers. He had lived in Charleston, W. Va., before transferring to Washington in 1952. He retired in the mid-1960s.

He lived in Bethesda and was a member of Chevy Chase United Methodist Church. A Mason for 34 years, he was a member of Almas Temple in Washington.

Survivors include his wife of 50 years, the former Virginia Jenkins, of Bethesda.

The family suggests that expressions of sympathy be in the form of contributions to the Heart Association.