Objective To provide an epidemiological perspective of the clinical profile, frequency, and determinants of poststroke hemiplegic shoulder pain. Design A prospective population-based study of an inception cohort of participants with a 12-month follow-up period. Setting General community and hospital within a geographically defined metropolitan region. Participants Multiple ascertainment techniques were used to identify 318 confirmed stroke events in 301 individuals. Among adults with stroke, data on shoulder pain were available for 198 (83% of the survivors) at baseline and for 156 and 148 at 4 and 12 months, respectively. Interventions Not applicable. Main Outcome Measures Subjective reports of onset, severity, and aggravating factors for pain and 3 passive range-of-motion measures were collected at baseline and at 4- and 12-month follow-up. Results A total of 10% of the participants reported shoulder pain at baseline, whereas 21% reported pain at each follow-up assessment. Overall, 29% of all assessed participants reported shoulder pain during 12-month follow-up, with the median pain score (visual analog scale score=40) highest at 4 months and more often associated with movement at later time points. Objective passive range-of-motion tests elicited higher frequencies of pain than did self-report and predicted later subjective shoulder pain (crude relative risk of 3.22 [95% confidence interval, 1.01-10.27]). Conclusions The frequency of poststroke shoulder pain is almost 30%. Peak onset and severity of hemiplegic shoulder pain in this study was at 4 months, outside of rehabilitation admission time frames. Systematic use of objective assessment tools may aid in early identification and management of stroke survivors at risk of this common complication of stroke.