BACKGROUND: We examined whether increases of intra-abdominal pressure would decrease compliance (C) of both lung and chest wall. METHODS: We measured airway and esophageal pressure in 10 anesthetized/paralyzed tracheally intubated patients during mechanical ventilation at the respiratory rate of 10 freq/min and the tidal volume of 10 ml/kg undergoing laparoscopic cholecystectomy. Measurements were made at 0 mmHg intra- abdominal pressure the (Pab) in supine position and at 15 mmHg Pab in 10 head-up (reverse Trendelenburg) position at 0, 5, 10 and 15 min. after CO2 insufflation. RESULTS: We found that abdominal carbon dioxide insufflation caused a marked increase in peak airway pressure, plateau pressure and esophageal pressure (p<0.05); a reduction in compliance of respiratory system and chest wall (p<0.05). CONCLUSION: These changes should be considered in patients such as those with pulmonary disease, undergoing laparoscopic cholecystectomy where increase in impendance may be critical.