Physical activity referral (PAR) schemes or concepts occur in varying forms. Because few physical activity intervention studies have been carried out in routine health care settings, it is difficult to translate research findings into daily practice. The aim of this study was to analyze the effectiveness of a PAR scheme implemented in routine primary health care. The study did not include a control group and was based on the ordinary staff's work efforts and follow-up measures. During a 2-year period, 6300 PARs were issued. Effectiveness was measured by an increase in self-reported physical activity. Half of the patients reached reported increased physical activity both at 3 months (49%) and at 12 months (52%). The proportion of inactive patients decreased from 33% at baseline to 17% at 3 months and 20% at 12 months. The proportion of patients who were physically active on a regular basis increased from 22% at baseline to 33% at 3 months and 32% at 12 months. Neither the patient's age nor the profession of the prescriber was associated with differences in effectiveness. The patient's activity level at baseline, the type of physical activity as well as the reason for the prescription were associated with increased physical activity.