A 19-year-old male developed renal failure after a laparotomy for liver trauma (urinary output of 30 ml/h, plasma creatinine 220 mumol/l). Surgical decompression of the abdomen was performed without any attempt at correcting the underlying pathology. This reduced the intraabdominal pressure (IAP) from 40 to 24 cm H2O and resulted in a massive diuresis (530 ml/h). Twenty-four hours later the plasma creatinine peaked at 280 mumol/l and then returned to within the normal range. This case report confirms that there is a direct relationship between IAP and renal function.