To investigate the frequency, course, and clinical correlates of disorientation following stroke, we administered the Mini-Mental State Examination orientation subtest to 177 alert patients 7-10 days and 3 months after stroke and 240 stroke-free nondemented subjects. Disorientation was defined as a score < or = 8/10. Seventy-two (40.7%) of the patients were disoriented 7-10 days after stroke and 39 patients (22.0% of the sample) remained disoriented 3 months later. A logistic regression analysis determined that persistent disorientation was significantly related to stroke status [odds ratio (OR) = 5.8], after adjusting for memory and attentional deficits and demographic variables. Among stroke patients, disorientation was associated with severe hemispheral stroke syndromes (OR = 7.7), but not infarct location or vascular risk factor history, after adjusting for memory and attentional deficits and demographic variables. Sensitivity and specificity analyses determined that disorientation was an inaccurate marker for dementia or deficits in memory or attention, while intact orientation was associated with a low probability of dementia or memory dysfunction in most patients but not preserved attention. We conclude that disorientation is common and persistent following stroke and associated with severe hemispheral stroke syndromes but not infarct location. While disorientation is a poor marker for dementia or deficits in memory or attention, intact orientation should suggest that cognitive functions are likely to be preserved.