Because of ongoing neuromaturation, youth with chronic alcohol/substance use disorders (AUD/SUD) are at risk for cognitive decrements during young adulthood. We prospectively examined cognition over 10 years based on AUD/SUD history. Youth (N = 51) with no AUD/SUD history (n = 14), persisting AUD/SUD (n = 18), or remitted AUD/SUD (n = 19) were followed over 10 years with neuropsychological assessments. Groups were compared at baseline and 10-year follow-up. Both AUD/SUD groups declined in visuospatial construction at year 10 (p = 0.001). Further, cumulative alcohol use (p less than 0.01) and drug withdrawal (p less than 0.05) predicted year-10 visuospatial function. Alcohol use predicted verbal learning/memory (p less than 0.05), while stimulant use predicted visual learning/memory (p = 0.01). More recent substance use predicted poorer executive function (p less than 0.05). In conclusion, heavy alcohol and other substance use from adolescence through young adulthood may produce cognitive disadvantages, including visuospatial and memory decline. Youth with heavy, chronic alcohol use and/or drug withdrawal symptoms may be at particular risk. (Contains 3 tables and 1 figure.)