Proteus syndrome is a complex disorder comprising malformations and overgrowth of multiple tissues. The disorder is highly variable affecting tissues in a mosaic pattern. A 2-year-old boy with Proteus syndrome, with epidermal verrucal naevus, hyperplastic lesions of connective tissue, hyperostosis, overgrowth of tubular bones, bilateral inguinal hernia, and juvenile intestinal polyposis was scheduled for vertebral magnetic resonance imaging (MRI) for further evaluation of malignancies. In addition to the pathological findings of this syndrome, potential complications such as difficult intubation, pulmonary hypertension, and pulmonary thromboembolism necessitate a careful preoperative and anesthetic preparation. MRI was performed under general anesthesia. There were no anesthetic complications. There are few previous reports on anesthesia in a patient with Proteus syndrome.