Mesenteric and omental cysts are rare intra-abdominal lesions. The rarity of these lesions, with an incidence of only about 1 in 140,000 hospital admissions, and the absence of characteristic clinical findings makes diagnosis difficult. Fourteen patients were treated for either mesenteric and/or omental cysts between 1965 and 1994 at Egleston Children's Hospital at Emory University. Of the 14 patients, 6 were female, 8 male; 3 were non-Caucasian, and 11 were Caucasian. They ranged in age from in-utero to 12 years old, with the most common presenting symptoms being abdominal distention (71%), pain (50%), vomiting (50%), and pain and distention (43%). Ultrasonography was the diagnostic method of choice. Other diagnostic modalities included intravenous pyelogram, barium enema, upper gastrointestinal series, CT scan, and MRI in selected patients. A single mesenteric cyst (79%) was most common, with only one patient (7%) having multiple mesenteric cysts as well as an omental cyst. The remaining two patients (14%) had single omental cysts. On gross examination, most (64%) were single, multilocular cysts. On pathological examination, the cysts ranged in size from 3.5 x 1 x 0.2 cm to 30 x 40 x 10 cm, with a mean of 14.9 x 11.5 x 4.7 cm. Six of the 14 contained fluid consistent with hemorrhage into the cysts. The most common treatment was simple excision (71%) followed by excision with partial bowel resection (29%). None received drainage alone as a treatment. There were no major postoperative complications and no reported recurrences of the cysts.