STUDY OBJECTIVE To evaluate the efficacy of a prophylactic saline patch and a prophylactic blood patch in prevention of headache following accidental dural puncture in obstetric patients. DESIGN Prospective, randomized, single-blind study on dural puncture headache occurrence and cessation. SETTING Inpatient obstetric unit at a metropolitan medical center. PATIENTS Seventy-four inpatients who underwent vaginal delivery or cesarean section following accidental dural puncture during administration of epidural anesthesia for labor and delivery. INTERVENTIONS Group 1 (n = 24), the control group, received fluids and analgesics. Group 2 (n = 30) received prophylactic epidural saline (40 to 60 ml) through the epidural catheter following completion of the obstetric procedure. Group 3 (n = 20) received autologous blood (15 ml) via epidural catheter following completion of the obstetric procedure. MEASUREMENTS AND MAIN RESULTS In Group 1, 21 of 24 patients (87.5%) developed headaches, with conservative management. In Group 2, 20 of 30 patients (66.7%) developed headaches, and in Group 3, 1 of 20 patients (5%) developed a headache. CONCLUSIONS The results of this study suggest that the administration of a prophylactic epidural blood patch is highly effective in the prevention of headaches following dural puncture, with headache frequency reduced from 87.5% to 5%.