A case of CO2 gas embolism occurring during retroperitoneal laparoscopic right radical nephrectomy in a 70-year-old-woman is reported. Patient's outcome was excellent after venous clamping, fluid loading and application of a positive and expiratory pressure. Gas embolism is a well documented complication of laparoscopic surgery, but has been rarely described in retroperitoneal laparoscopy for urologic procedure. The retroperitoneal surgical site, the major surgical procedure with vessel manipulation and the left lateral position seem to be the risk factors for gas embolism in this case.