The presence of gas in the portal venous system is considered an ominous sign often mandating immediate exploratory laparotomy; however, there are numerous reports of benign incidences of this finding. This report describes a case of portal venous gas after extracorporeal shockwave lithotripsy. The patient had the rare complication of obstructive pyleonephritis that progressed to sepsis and subsequently underwent a negative exploratory laparotomy. It is suggested that the radiographic finding of portal venous gas should be correlated with the likely cause and overall clinical picture.