Omental infarction is a rare cause of acute abdominal pain, and the cause of omental infarction itself remains unknown. The diagnosis of omental infarction is occasionally made intra-operatively, because it is poorly known and presents no specific clinical features. Therefore omental infarction should always be considered in the differential diagnosis of abdominal inflammatory processes, mainly those affecting the right lower quadrant. The increasing use of computed tomography in cases of acute abdomen has facilitated the diagnosis of omental infarction in the pre-operative period. Here, we present the case of a 36-year-old, overweight female patient with clinical symptoms of acute abdomen. Computed tomography of the abdomen revealed indications of omental infarction. The patient was treated conservatively with analgesics and a nonsteroidal anti-inflammatory. The clinical evolution was favorable.