Recent studies suggest that morbidity and mortality in patients with pancreatic abscess can be lessened if controlled open lesser sac drainage (COLD) is performed rather than traditional closed drainage (CD). To determine whether the outcome of patients treated by COLD was more favorable, 81 consecutive patients with pancreatic abscess managed surgically between 1966 and 1985 were studied. COLD, consisting of initial wide debridement of the abscess cavity, open packing, suction drainage, repeated operative pack changes, and lavage was used in 17 patients and CD in 64 patients. Age, sex, etiology of pancreatitis, and radiographic and laboratory findings were similar between treatment groups. However, the number of patients with overt systemic sepsis and those at increased risk of death based on Ranson signs associated with the predisposing episode of pancreatitis were greater in the COLD group than in the CD group (100% vs. 61%, and 92% vs. 44%, respectively; p less than or equal to 0.05 for both). Overall mortality in COLD and CD patients was 18% and 44%, respectively (p less than 0.05). However, in patients at increased risk of death (positive Ranson signs greater than or equal to 3), mortality after COLD and CD was 18% and 70%, respectively (p less than 0.05). Controlled open drainage may be the treatment of choice in patients with pancreatic abscess precipitated by severe pancreatitis (Ranson signs greater than or equal to 3) and associated with overt systemic sepsis.