The quality of the evidence that supports the use of medical treatment before conservative surgery for endometriosis is manifestly poor, and no recommendations can be made based on the results of the published studies. There are practical advantages inherent to this schedule, but whether this translates into better conception rates and reduced pain recurrence rates is unproven. The effect of drug therapy after surgery can be assessed better as data from seven true randomized, controlled trials are available. The results of the current review do not support the notion that suppressing ovarian activity postoperatively increases the long-term pregnancy rate. As far as pelvic pain is concerned, more data are needed to verify the reduced symptoms recurrence rate found in four trials in women who were allocated to postoperative medical therapy, particularly in view of the different results obtained in some of the considered studies. The observed differences among various drugs used before or after surgery are limited in clinical terms and, in the absence of formal randomized comparisons, are difficult to interpret. Because of their tolerable side effects and limited cost, progestins with or without estrogens should be considered strongly as first-line postoperative medical treatment if and when suppression of ovulation after conservative surgery is deemed opportune.