Contrary to metastatic tumors of the omentum, primary tumors of the omentum are very rare. A 10-year-old girl presented with low abdominal pain. Imaging studies showed a multiseptated hemorrhagic tumor. The mass from the omentum was removed completely and confirmed as a malignant rhabdoid tumor. Despite aggressive chemotherapy, she died after 9 months due to disease progression. We report one case of primary malignant rhabdoid tumor of the omentum for the first time.