The purpose of the investigation was to evaluate the efficacy of a slow bupivacaine infusion at postoperative surgical sites in immediate breast reconstruction patients. This prospective study included 16 patients who underwent autologous breast reconstruction with a latissimus dorsi pedicled flap immediately after mastectomy. A two-site infusion kit with dual split-flow catheters was secured at the operative sites before skin closure. A spring-loaded disposable pump then infused 0.25% bupivacaine at a rate of 2.08 cc per catheter per hour for 48 continuous hours. Patient pain levels, nausea/emesis, and oral and intravenous narcotic use were then recorded at 12-hour intervals. Medication use was converted to pain units for results comparison (one pain unit was defined as the equivalent of 10 mg of intravenous morphine). A retrospective control group comprised 16 consecutive patients from December of 1999 to October of 2002 who underwent the same surgery by the same surgeon using oral and intravenous pain medications. The experimental group demonstrated a more than fivefold decrease in the use of oral and intravenous pain medications compared with the historical controls (6.7 versus 1.7 pain units) (p < 0.001). The overall pain experienced by the catheter patients was nearly twofold less than the pain experienced by those without the catheter (1.8 versus 3.4 on the visual analog pain scale) (p < 0.017). Twenty-eight percent of the experimental group experienced nausea/emesis compared with 61 percent in the control group. No complications occurred with the use of the pain pump catheter. A 48-hour infusion of 0.25% bupivacaine significantly decreases the need for postoperative narcotics and the over-all pain experience in immediate breast reconstruction patients. This effective form of pain control may alleviate patient concerns of postoperative pain and may safely downstage many plastic surgery procedures, such as immediate breast reconstruction, and many cosmetic procedures to same-day status when the primary indication for admission is pain management.