The extent and nature of multiple jobholding by persons who reported income from farm self-employment was studied by examining Social Security data for 1957, 1958, and 1959. Hypotheses were that multiple jobholding is a method used by farmers who are underemployed in agriculture to supplement earnings and that off-farm sources of employment tend to be subject to cyclical instability and diminishing employment levels. It was found that the incidence of multiple jobholding by farm operators was widespread geographically, inversely related to age, not related to income from self-employment, and not a continuous situation. The most frequent source of off-farm wage employment was some unit of government, especially among older, white farm operators with higher levels of self-employment income. Younger farm operators were more frequently employed in manufacturing, mining, and wholesale and retail trade. Earnings from off-farm employment were lowest in the South and highest in the Northeast and Pacific regions. Multiple jobholding fell in three categories: (1) a first step in changing occupations, (2) a sporadic income supplement, and (3) a substantial income source. (JM)