OBJECTIVES Worldwide, the association of passive smoking with development of stroke has been ascertained. However, it remains unknown of the magnitude of the association in the Chinese population. We thus systematically reviewed the published studies worldwide. METHODS We searched Medline, EMBASE, and three other Chinese databases from their inception to June, 2008. We included case-control and cohort studies that investigated the association of smoking with stroke, and that provided data on the magnitude of the association. Two reviewers screened the eligibility, assessed the extent of the bias, and extracted data independently. We obtained the unadjusted and adjusted estimates of studies. We pooled the trial data using the random-effect model and explored the heterogeneity by the pre-specified variables. RESULTS We included 49 studies (n=58,872), 8 of which were cohort studies (n=42,755) and 41 case-control studies (cumulative cases 7 883, controls 9 590). Smoking increased the risk of stroke by 75% (OR 1.75, 95%CI 1.51 to 2.03). Pooling of adjusted estimates of 31 studies (n=26,028) showed the risk of stroke was increased by 81% in smokers (1.81, 1.57 to 2.08). The magnitude of the association was not statistically different in different type of strokes: hemorrhagic stroke 1.65 (1.29 to 2.11) and ischemic stroke 1.79 (1.20 to 2.68). No dose-response relationship was found between amount of smoking and the risk of stroke. CONCLUSIONS The increased risk of stroke associated with smoking in the Chinese population has been ascertained.