Blue rubber bleb nevus syndrome (BRBNS) is a rare syndrome characterized by multiple vascular malformations of varying size and appearance that present predominantly on the skin and within the gastrointestinal tract and, less often, in other internal organs. Gastrointestinal lesions of BRBNS can cause acute or chronic bleeding, and the treatment is challenging. In this case, we reported a successful treatment of vascular malformations in all segments of gastrointestinal tract, including the small intestine, by endoscopic sclerotherapy, in a 10-year-old boy with BRBNS.