Blue rubber bleb nevus syndrome (BRBNS) is a rare disorder with characteristic vascular malformations of the skin, gastrointestinal system, and, less often, other organ systems. The characteristic cutaneous lesions consist of deep-blue, soft, rubbery blebs, which are easily compressible. The most serious complication is abundant gastrointestinal bleeding. We describe the case of an 8-year-old girl with diagnosed BRBNS who had multiple venous malformations all over her body, importantly, throughout the gastrointestinal tract, mouth, esophagus, stomach, small bowel, and colon. She presented with recurrent massive gastrointestinal bleeding and soft tissue hematoma despite prednisolone and α-interferon therapy. We started low-dose sirolimus as an antiangiogenic agent. The vascular masses were reduced rapidly and there was no gastrointestinal bleeding and muscular hematoma after sirolimus therapy. There was no drug adverse reaction at 20-month follow-up. To the best of our knowledge, this is the first report related to the use of sirolimus in a patient with BRBNS.