Klippel-Trenaunay-Weber syndrome (KTWS) is a rare disease characterized by vascular malformations, port-wine staining, and soft tissue and bone hypertrophy. Lesions occur in the lower extremities in 95% of cases, whereas only 5% occur in the upper extremities. Several case reports have described the treatment of fractures in the lower extremities in patients with KTWS. However, the risk of massive bleeding, bone deformity, and poor bone quality can lead to suboptimal surgical outcomes. No reports describing the treatment of forearm shaft fractures in KTWS could be found in the English-language literature. Intramedullary nailing is difficult due to the deformed bone and the risk of nonunion. Open reduction and internal fixation (ORIF) should be considered with caution in KTWS patients due to the risks of intraoperative bleeding and wound problems. The authors report that satisfactory results were obtained with ORIF after preoperative vascular embolization in a 60-year-old KTWS patient with fractures in both bones of the forearm.