Lipoma of the greater omentum is observed very rarely, particularly in the childhood. We report a case of large 10x11x8 cm asymptomatic lipoma of the greater omentum, which was diagnosed incidentally. Well-encapsulated mass with a homogeneous internal structure and high echogenicity--these signs of ultrasound and computed tomography allowed us to suggest a lipoma. At laparotomy lipoma of greater omentum in torsion was found. The excision of the tumor and omentectomy was performed. The histopathological diagnosis was lipoma with focal necrosis areas.