Abstract Background and purpose Reliable assessment of the determinants of major pathological types of stroke is dependent on the accuracy of diagnosis in population-based studies. We evaluated the diagnostic accuracy of stroke types in a large community-based cohort study involving health records collected in China. Methods In 2004–08, >0.5 million adults aged 30–79 years were recruited from general populations of 10 diverse areas (5 urban, 5 rural) in China. During an approximate 7-year follow-up, 37,694 stroke cases had been reported by linkage to electronic health records from disease-specific and mortality registries and from national health insurance agencies. For all reported stroke cases, hospital medical records were retrieved systematically and relevant data extracted for subsequent adjudication by specialists using bespoke electronic platforms. Results Among all reported incident stroke cases, 80% were ischaemic stroke (IS), 17% were intracerebral haemorrhage (ICH), and 1% were subarachnoid haemorrhage (SAH). To date, medical records have been retrieved for 29,632 cases, with reports of stroke diagnosis verified by public health staff in 27,115 (92%) cases, of which 3,778 (14%) were secondary diagnoses. Evidence of neuroimaging was found in 92% of all verified stroke cases. Of 23,337 primary stroke cases sent for specialist adjudication, a diagnosis of pathological stroke type was confirmed in 19,718 cases with the positive predictive values being 82.4% (95% confidence interval [CI], 82.0% - 82.8%) for IS, 97.8% (97.6 - 97.9) for ICH, and 98.2% (98.1 - 98.3) for SAH. Overall, the strength of association of systolic blood pressure was over 6-fold greater for confirmed than non-confirmed stroke cases and was nearly 3-fold greater for confirmed ICH than IS cases. Diagnostic accuracy by stroke type Reported Retrieved Verified Adjudicated Confirmed Approximate 95% CI n n % n % n % n PPV, % IS 30,143 25,477 85 23,551 92 20,045 85 16,515 82.4 (82.0–82.8) ICH 6,484 3,486 54 3,079 88 2,919 95 2,854 97.8 (97.6–97.9) SAH 557 397 71 326 82 279 86 274 98.2 (98.1–98.3) Other 510 272 53 159 59 94 59 75 79.8 (79.4–80.2) IS indicates ischaemic stroke; ICH, intracerebral haemorrhage; SAH, subarachnoid haemorrhage; and PPV, positive predictive value. Conclusions The overall diagnostic accuracy of pathological stroke types obtained from hospital records in China is comparable to reports from Western populations. Despite advances in electronic healthcare records, reliable classification of stroke types requires clinical adjudication using additional relevant investigations. Acknowledgement/Funding Kadoorie Charitable Foundation, UK Wellcome Trust & National Natural Science Foundation and National Key Research and Development Program of China