The effects of pneumoperitoneum on peak venous flow velocity in the common femoral vein and the vena cava have already been studied. The results suggested that venous stasis occurs during surgical pneumoperitoneum. This study determines the effects of pneumoperitoneum on the overall venous outflow resistance of the lower limbs. Venous outflow resistance was measured during surgical procedures by impedance plethysmography in 12 patients undergoing laparoscopic cholecystectomy, 4 patients undergoing laparoscopic herniorrhaphy, 4 patients undergoing conventional cholecystectomy, and 2 patients undergoing conventional herniorrhaphy. Venous outflow resistance did not change significantly during laparoscopic cholecystectomy or herniorrhaphy. No difference in venous outflow resistance between laparoscopic cholecystectomy and herniorrhaphy was found. During pneumoperitoneum. no obstruction to total lower limb venous outflow could be demonstrated, indicating that venous stasis in the limbs did not occur, and consequently, flow in the iliac and inferior caval veins was not compromised. Hypothetically, active vasodilatation resulting from mild compression may explain this. In our view, no special measures to prevent deep venous thrombosis have to be taken during laparoscopic procedures.