Several tests of visuospatial cognition are known to be sensitive to chronic alcohol abuse, but the consequences of combined abuse of alcohol and other drugs on these measures in not known. To address this issue, groups that had abused only alcohol, alcohol and marijuana, or alcohol and multiple other drugs (Alc/Poly) were compared to community controls. Testing occurred after at least 3 weeks of treatment for the drug abusers. On all measures of visuospatial perception and construction and on all measures of visuospatial learning and memory, all groups of alcoholics were impaired relative to controls, but there were no significant differences among the groups that abused alcohol. By contrast, on all measures of geographical knowledge that required place localization, subjects in the Alc/Poly group were impaired while subjects who abused only alcohol or alcohol and marijuana performed as well as controls. Measures of alcohol consumption, mood or childhood or adult attention deficit were not consistently correlated with test performance.