The authors report a rare case of mesenteric cyst in a 36 years old woman. These cysts have a pathogenesis that primarily may be ectopic lymphatic tissue and their most common site is in the small bowel mesentery, especially of the ileum. In the case reported the cyst was located in the right mesocolon. Mesenteric cysts can appear as chronic abdominal pain, a painless abdominal mass, or acute abdomen. Diagnostic aids include abdominal computed tomography and sonography, that usually make diagnosis of mesenteric cyst. Treatment of choice is enucleation; resection of the adjacent bowel may occasionally be necessary.