Human sparganosis is a rare parasitic disease caused by infection with the tapeworm Sparganum, the migrating plerocercoid(second stage) larva of Spirometra species. Sparganosis usually involves subcutaneous tissues and/or muscles of various parts of the body, but involvement of other sites such as the brain, eye, peritoneopleural cavity, urinary track, scrotum, and abdominal viscera has also been documented. Infections caused by sparganum have a worldwide distribution but are most common in Southeast Asia such as China, Japan, and South Korea. Rectal sparganosis is an uncommon disease but should be considered in the differential diagnosis of unusual and suspicious rectal submucosal tumors. We report a case of rectal sparganosis presenting as rectal submucosal tumor. We performed endoscopic submucosal dissection of the rectal submucosal tumor. The sparganosis was confirmed based on the presence of calcospherules in the submucosal layer on histological examination. Moreover, the result of the immunoglobulin G antibody test for sparganosis was positive but became negative after endoscopic submucosal dissection. Though rare, rectal sparganosis should be considered in the differential diagnosis of rectal submucosal tumor-like lesions. This case suggests that physicians should make effort to exclude sparganosis through careful diagnostic approaches, including detailed history taking and serological tests for parasites. In this report, we aimed to highlight the clinical presentation of Sparganum infection as a rectal submucosal tumor. Human sparganosis is a rare parasitic disease caused by infection with the tapeworm Sparganum, the migrating plerocercoid (second stage) larva of Spirometra species. Sparganosis usually involves subcutaneous tissues and / or muscles of various parts of the body, but involvement of other sites such as as the brain, eye, peritoneopleural cavity, urinary track, scrotum, and abdominal viscera has also been documented. Infections caused by sparganum have a worldwide distribution but are most common in Southeast Asia such as China, Japan, and South Korea. Rectal sparganosis is an We reported a case of rectal sparganosis presenting as rectal submucosal tumor. We performed endoscopic submucosal dissection of the rectal submucosal tumor. The sparganosis was confirmed based on the presence of of calcospherules in the submucosal layer on histological examination. Moreover, the result o Although the rare and rectal sparganosis should be considered in the differential diagnosis of rectal submucosal tumor-like lesions careful diagnostic approaches, including detailed history taking and serological tests for parasites. In this report, we aimed to highlight the clinical presentation of Sparganum infection as a rectal submucosal tumor.