This report is from a longitudinal study of a community sample of African-American males (N = 197) on the relationship of the degree of earlier substance use/abuse up to average age 24, to vocational performance (employment and occupational level) 2 1/2 years later (at average age 26 1/2). The statistical analyses included numerous control variables developed from prospective data of the National Collaborative Perinatal Project, on the subjects and on their families from the subjects' birth to age 7, and from their school behavior and academic performance up to age 16, which may have influenced their vocational-occupational behavior during early adulthood. It was found that greater earlier marijuana use and greater earlier alcohol use predicted, to a significant degree, poorer occupational performance.