New technology, nonfarm labor conditions, farm prices, and government policies have altered both the size and composition of the hired farm work force. Average annual farm employment dropped 70 percent between 1945 and 1987. Although family members continue to provide the major portion of agricultural labor, hired farmworkers contribute relatively more labor now, 36 percent in 1987 compared with 22 percent in 1945. The numbers of domestic workers and legally admitted foreign nationals doing hired farmwork have stabilized in recent years after wide variations responding to wartime labor shortages, changes in government work programs, and increased mechanization. The number of illegal aliens working in U.S. agriculture is unknown owing to lack of accurate data, but the increase in apprehensions of these aliens after 1965 suggests a large population. The Immigration Reform and Control Act of 1986 will probably significantly influence the composition of the hired farm work force.