Background Despite the potential of clinical practice guidelines to improve patient outcomes, adherence to guidelines by prescribers is inconsistent. Objective The aim of the study was to determine whether an approach of introducing an educational programme for prescribers in the hospital combined with audit and feedback by the hospital pharmacist reduces non-adherence of prescribing physicians to key pharmacotherapeutic guidelines. Setting This prospective intervention study with a before–after design evaluated patients at surgical, urological and orthopaedic wards. Method An educational program covering pain management, antithrombotics, fluid and electrolyte management, prescribing in case of renal insufficiency, application of radiographic contrast agents and surgical antibiotic prophylaxis was presented to prescribers on the participating wards. Hospital pharmacists performed medication safety consultations, combining medication review of patients who are at risk for drug related problems with visits to ward physicians. Main outcome measure The outcome measure was the proportion of the admissions of patients in which the physician did not adhere to one or more of the included guidelines. Difference was expressed in odds ratios (OR) with 95% confidence intervals (CI). Multivariable logistic regression analysis was performed. Results 1435 Admissions of 1378 patients during the usual care period and 1195 admissions of 1090 patients during the intervention period were included. Non-adherence was observed significantly less often during the intervention period [21.8% (193/886)] as compared to the usual care period [30.5% (332/1089)]. The adjusted OR was 0.61 (95% CI 0.49–0.76). Conclusion This study shows that education and support of the prescribing physician can reduce guideline non-adherence at surgical wards.