Hernias recur primarily for two reasons: (1) attrition of tissue due to altered collagen metabolism and (2) tension on the suture line. Human tissue alone cannot be used to counteract these causes; a satisfactory prosthesis is needed if results of herniorrhaphy are to improve. We have had a large personal experience with monofilament polypropylene mesh (Marlex), using it to repair more than 5,000 hernias of all types over a period of 25 years. We have found it to be nonallergenic, nononcogenic, and highly resistant to infection. It serves as an effective and permanent barrier to protrusion through the floor of the inguinal canal and is readily incorporated into tissue with virtually no foreign-body reaction. Postoperative discomfort is minimized because there is no tension on the sutures and the operation is easily performed using a local anesthetic. The patient may leave the ambulatory care center within hours and return quickly to unrestricted activity with confidence.