To identify the sentinel lymph node in melanoma patients, intradermal injection of a radiocolloid tracer and a blue dye are commonly used. Life-threatening side effects of isosulfan blue and Patent Blue V have been well described. However, to the extent of our knowledge, only two life-threatening events with intradermal methylene blue dye have been reported, and none has been reported in the pediatric population. We report a case of a 6-year-old white girl with spitzoid melanoma on her right forearm. She had lymphoscintigraphy under general anesthesia and was taken to the operating room intubated. Intradermal methylene blue (0.2 ml) was injected around the lesion, and after 5 min, wide complex bradycardia was noted and progressed to asystole within less than 1 min. Cardiopulmonary resuscitation was started. Multiple doses of resuscitative drugs were administered, and electrical cardioversion was given twice as well. She recovered completely and transferred to the intensive care unit.