The total cost to the patient is an important consideration in the selection of antimicrobials for prevention and treatment of post-cesarean section endomyometritis. We compared the cost to the patient of commonly used therapeutic and prophylactic agents in a theoretical model population of 450 women who were delivered by cesarean section. Cost of the drug alone on a per gram, per dose, or per day of therapy basis is not an accurate way of estimating the cost eventually paid by the patient. The therapeutic efficacy, frequency of administration, and need for ancillary services for each treatment regimen affect significantly the patient's costs.