This study examines the determinants of income diversification of farm households in the United States. Farm households allocate their time between farm and off-farm activities to help stabilized household income (consumption). What characterizes those households who engage in off-farm activities? Is there any pattern over time? Using 1999, 2003 and 2007 farm-level data from the USDA’s Agricultural Resource Management Survey (ARMS), this study estimates intensity of off-farm income (or income diversification). The results show that older operators, full owners, and small farms have higher intensity of off-farm income in total household income. In contrast, dairy farms, vertically coordinated farms and farms located in the Southern and Pacific regions have lower intensity of off-farm income. In other words, household incomes of these farms are less likely to be diversified.