Background. The aim of this study was to investigate whether established risk factors for stroke in patients admitted to health care for first-ever stroke had been detected and treated in primary health care. Methods. In a retrospective study in Nacka municipality, Stockholm County, Sweden, with about 70 000 inhabitants, we included all men and women admitted to health care due to first-ever stroke between October 1999 and March 2001. Data on 187 such patients, with a mean age of 75 years, were obtained from medical registers. Main outcome measures were detection and treatment of risk factors for stroke including hypertension, diabetes, atrial fibrillation, smoking, alcohol abuse, and overweight/obesity. Results. In a majority of patients seen in primary health care with hypertension and diabetes, those risk factors were detected and treated (75.6% and 75.0%, resp.). Fewer patients with atrial fibrillation received treatment (60.9%). Treatment of lifestyle factors was difficult to assess because of lack of data in the medical records. Conclusions. Primary prevention of stroke in primary health care needs to be improved, especially when atrial fibrillation and lifestyle-related risk factors are present. Health policies need to target not only the public, but also general practitioners and other health care professionals.