125 patients suffering from diverticulitis of the colon were treated during 11 years. 51 patients were treated conservatively, 74 operatively; 14 of them were emergency cases. The preferred method is the primary sigmoidectomy as an elective operation (single stage procedure without colostomy). The perioperative antibiotica prophylaxis is given as a routine measure. There was no operative death. The results in both groups and the follow-up investigation of 73 patients are reported.