• Nausea, vomiting, normal serum amylase values, and clinical and roentgenographic evidence of epigastric or retrogastric masses were common findings in 19 patients with pseudocysts and eight with abscesses treated from 1969 through 1974. Helpful criteria for distinguishing between pancreatic pseudocyst and abscess were signs of sepsis. Thirteen pseudocysts were diagnosed preoperatively and seven, including one that developed after drainage of an abscess, at operation. All abscesses except one were diagnosed preoperatively. No undiagnosed pancreatic abscesses were found at autopsies performed during this period. Treatment of pseudocysts consisted of cystogastrostomy for 13 patients and external drainage for six. All abscesses were drained externally, with three cures, three recurrences, one persistent fistula, and one pseudocyst later treated by cystogastrostomy; one patient with a recurrent abscess was successfully treated by reoperation and external drainage, whereas two in whom operation was delayed died. This study indicates that the preferred treatment for pancreatic pseudocysts was cystogastrostomy, but external drainage was satisfactory. External (sump) drainage was preferred for pancreatic abscess. (Arch Surg 112:42-45, 1977)