To determine the factors that allow early recognition of injuries to the intrathoracic and intra-abdominal organs in patients with penetrating wounds to the lower thorax and abdomen with site of entrance located in the back or flanks, we retrospectively analyzed the cases of 77 such patients. There were 65 stab wounds (85%) and 12 gunshot wounds (15%). The injuries were confined to the abdomen in 46 (60%); 39 were stab wounds and seven were gunshot wounds. The wounds were confined to the chest in 24 patients (31%) and involved both the chest and abdomen in seven cases (9%). Of the 53 abdominal wounds, 21 necessitated celiotomy; in 20 of them, an intra-abdominal organ was found injured, and one patient died (1.9%). Of the 24 injuries confined to the chest, only one patient required emergency thoracotomy due to massive hemorrhage; all 24 patients survived. All of the seven thoracoabdominal injuries, two produced by gunshot and five by stabbing, necessitated celiotomy. Most patients with gunshot wounds to the back and flanks require celiotomy, but a selective therapy can be safely used in patients with stab wounds. The rate of negative exploratory celiotomy was less than 5%; the mortality was 1.3%.