This study was embedded within the prospective population-based Rotterdam Study 8 and Rotterdam Scan Study. 9 From 1990 to 2012, we continuously followed up 13 894 participants (mean age, 65.5±10.3 Background and Purpose-Left-sided strokes are reported to be more common than right-sided strokes, but it is unknown whether they occur more often or are simply recognized more easily by clinicians. In a large unselected communitydwelling population, we examined the frequency of clinical left-and right-sided strokes and transient ischemic attacks (TIAs) and compared it with the frequency of left-and right-sided infarcts on MRI. Methods-This study was conducted within the population-based Rotterdam Study. Between 1990 and 2012, 13 894 participants were followed up for first-ever stroke and TIA. MRI scans were performed within a random subgroup of 5081 persons and were rated for the presence of supratentorial cortical and lacunar infarcts. We compared frequencies of left-and right-sided strokes, TIAs, or MRI infarcts using binomial and Fisher exact tests. Results-After a mean follow-up of 9.6 (±6.0) years, 1252 patients had a stroke, of which 704 were ischemic, and 799 participants had a TIA.