BACKGROUND: Medication errors occur regularly in surgical patients, especially due to transfer problems at the time of hospital admission. A method for decreasing the error rate is medication reconciliation by hospital pharmacists as part of a preoperative clinic. The role of pharmacy technicians in this process has not been studied. OBJECTIVE: To study the use of pharmacy technicians in medication reconciliation by measuring the effect of early reconciliation in the preoperative clinic on medication and allergy discrepancies and on inadvertent continuation of antithrombotics. A secondary objective was to study the effect of community pharmacist follow-up on recommendations to discontinue antithrombotic therapy. METHODS: During the preintervention measurement period, patients received usual care by anesthesiologists, who recorded the medication and documented allergies of the patient. The intervention consisted of the addition of a pharmacy technician to the preoperative screening clinic to perform the same tasks as anesthesiologists as related to medication reconciliation. If necessary, the patient was advised on stopping the antithrombotic. On the day that the patient was supposed to stop the antithrombotic, that person's community pharmacist contacted the patient to determine whether this had been done. The main outcome measures were the proportions of patients with one or more medication discrepancy, one or more allergy discrepancy, and one or more antithrombotic error. RESULTS: In the preintervention period, 204 patients were evaluated; 93 were included in the postintervention analysis. The proportion of patients with one or more medication discrepancy (RR 0.29; 95% CI 0.12 to 0.71) was statistically significantly reduced in the postintervention group. The proportions of patients with one or more allergy discrepancy (FIR 0.76; 95% CI 0.35 to 1.64) and one or more antithrombotic errors (RR 0.18; 95% CI 0.02 to 1.33) were reduced, but not significantly. Follow-up by the community pharmacist did not identify any patients who had not followed the preoperative clinic's advice on temporarily withholding their antithrombotics. CONCLUSIONS: The results of this study show that pharmacy technicians can be successfully assigned to a preoperative clinic, resulting in a statistically significant decrease in medication discrepancies.