To define the role of percutaneous catheter drainage in the initial management of diverticular abscess, we reviewed 19 patients who were followed for an average of 17.4 months after drainage. All patients had large paracolic or pelvic abscesses with a mean size of 8.9 cm. There were no complications related to catheter placement, and 15 patients (79 percent) required drainage for less than 3 weeks. Sepsis resolved rapidly, and only two patients (11 percent) had persistent fever or leukocytosis beyond the third day of drainage. Routine sinography revealed fistulous communications to the colon in nine patients (47 percent), but only three (16 percent) had grossly feculent drainage. Fourteen patients (74 percent) completed the treatment plan of preoperative catheter drainage followed by single-stage sigmoid colectomy and primary anastomosis without complications. Two patients refused operation, one of whom died 16 days postoperatively from recurrent sepsis and end-stage pulmonary disease. The three patients with fecal fistulas all had inadequate control of infection, suggesting the need for early operation and fecal diversion in such cases. We conclude that preoperative percutaneous catheter drainage obviates the need for colostomy and multiple-stage surgery in approximately three-fourths of patients with large diverticular abscesses.