The addition of laparoscopy to the urologist's surgical armamentarium has introduced the physiologic changes associated with these prolonged surgical procedures. An understanding of the effects of the pneumoperitoneum is especially important as the complexity of laparoscopic urologic procedures continues to increase. Laparoscopy has been used not only for diagnostic purposes but for therapeutic management (e.g., nephrectomy) and reconstruction (e.g., pyeloplasty) of urologic disease processes. As a minimally invasive method of surgical management, this form of treatment has been applied to the higher-risk, more debilitated patient who may be considered too sick for conventional open surgery. With the evolution of laparoscopy has come an extensive research experience, from animal and clinical studies, evaluating the various systemic physiologic effects of insufflating gas into the body and elevating intra-abdominal or retroperitoneal pressures. In otherwise healthy patients, these changes may not be clinically significant. The elderly or debilitated patient, however, may have a diminished threshold for the effects of these physiologic changes. A clear understanding of the various physiologic effects of laparoscopic surgery allows the surgical team to minimize the risks and to maximize the potential advantages of this surgical approach in all patients.