33 out of 135 patients (24.5%) developed suture insufficiency after Billroth I-resection. There was no selection of patients in respect of elective, corrective and emergency surgery. The diagnosis is always possible on the grounds of clinical criteria. On the contrary, the early radiographic postoperative direct proof of suture insufficiency is not always possible (14 out of 24 cases). Indirect radiographic signs, such as gastroatonia, delayed gastric emptying, medio-paragastric atypical fluid levels may be relied upon and likewise on signs of the upper abdominal and intestinal stasis, such as radiographic intestinal fluid level, or more frequently pleural effusion on the left side. Typical laboratory changes are absent in the early phase. The rare, but threatening early insufficiency (first until third postoperative day) requires immediate relaparotomy. Dehiscence comes into existence not before the fourth and sixth postoperative day (late insufficiency). They can be treated conservatively. By adequate drainage late complications should not be expected. The period of hospitalization is prolonged over eight days on an average. If the fistula persists, surgical closure should be considered after 30 days because of the increased possibility of severe arrosive haemorrhage.