Laparoscopy was performed in 259 women. Under general anesthesia, after administering muscle relaxants, and with the patient in stirrups and horizontal position, a nondisposable Veress needle was inserted at the umbilicus or left upper quadrant site with carbon dioxide (CO2) flowing at 1 L/minute. We measured initial intraabdominal pressure in the first 52 women (group 1), pneumoperitoneum pressure (up to 15 mm Hg) at 1-L intervals in the next 102 women (group 2), and CO2 volume required for pressures of 10, 15, 20, and 25 mm Hg in the final 102 women (group 3). In three patients the procedure was abandoned. The primary trocar and laparoscope were introduced at pressure of 25 mm Hg and the entry site and abdominal contents were inspected before desufflation to 15 mm Hg and Trendelenburg position. Medians and means of initial intraabdominal pressure were 4 and 4.09 mm Hg (SD 1.34 mm Hg, range 2-8 mm Hg). This was always below interstitial pressures measured in the abdominal wall and during inadvertent insertion into omentum (5) and colon (2). Correlation between initial intraperitoneal pressure and patients' parity, weight, and body mass index was minimal. Mean CO2 volumes at 10, 15, 20, and 25 mm Hg were 3.7, 5.1, 5.9, and 6.5 L, respectively. No major complications were encountered. An initial intraabdominal pressure of 8 mm Hg or below always indicates correct placement of the Veress needle regardless of the patient's body habitus. Pressures greater than 8 mm Hg indicate interstitial placement including colon. Adequate pneumoperitoneum is determined by CO2 insufflation to a pressure of 25 mm Hg and not by a preconceived volume of CO2.