This is the first report, to our knowledge, of a case of massive subcutaneous emphysema during totally preperitoneal laparoscopic hernia repair causing a "respiratory acidosis" with a systemic pH 7.20 and a pCO2 of 64 and PO2 of 84. The acidosis was corrected by increased mechanical ventilation. It appears that because of its lack of defined borders, the preperitoneal space is particularly vulnerable to the formation of massive subcutaneous emphysema. Thus, there is a large potential surface area for CO2 absorption. The complication may be prevented by increased attention to the length of fascial incisions, inflation of balloon expanding devices, and securing gripping devices in the port sites.