The Authors report a case of biopsy-proven malignant hyperthermia in a pediatric patient who underwent general anesthesia with halothane and succinylcholine for foot surgery, in whom the presenting symptom was isolated postoperative myoglobinuria. The above syndrome, in the absence of a positive family history, may present itself with a set of minor and atypical symptoms, thus being often underestimate. The need for further investigating all the cases of postoperative myoglobinuria is stressed by the Authors, which also consider muscular biopsy for inclusion among routine investigations. In the case reported here, six months later, a new surgical operation was done safely with spinal anesthesia using hyperbaric bupivacaine.