Background Malignant hyperthermia syndrome is a hereditary pharmacogenetic disorder of skeletal muscle characterized by hypermetabolic state related to the exposure of volatile anesthetic gases or depolarizing muscle relaxants. It is an infrequent entity that occurs in genetically predisposed individuals, with a very low incidence in pediatrics (1 in 10,000-15,000 anesthetic procedures). Case report We report a case of malignant hyperthermia related to exposure to sevoflurane during adenoidectomy surgery in a 6-year-old female. The patient presented with tachycardia, hypercapnia, and hyperthermia, requiring two successive doses of dantrolene sodium administration, with an adequate response to the treatment. Conclusions Malignant hyperthermia syndrome is a rare condition in pediatric patients that should be detected in early stages since it is essential to initiate the treatment as soon as possible.