Objective: To alert pediatricians about the importance of a careful investigation on recurrent apparent life-threatening events. Reports of the association of these events with congenital myasthenic syndromes were not found. Case description: A seven-month-old infant with recurrent apparent life-threatening events was admitted for investigation. During hospital stay, she presented cyanosis and respiratory failure, requiring mechanical ventilation for three days. After clinical improvement, hypotheses of gastroesophageal reflux and pulmonary aspiration were ruled out. The presence of eyelid ptosis, general hypotonia and weak crying led to the suspicion of congenital myasthenia, which was confirmed. Treatment with oral piridostigmine led to neurological and nutritional normalization, without any other apparent life-threatening event during the next three years. Comments: The careful etiological investigation of apparent life-threatening events may lead to rare diagnosis that requires specific treatments, such as congenital myasthenia.311121123National Institutes of Health consensus development conference on infantile apnea and home monitoring, Sept 29 to Oct 1, 1986 (1987) Pediatrics, 79, pp. 292-299. , Autoria não referidaRomaneli, M.T., Fraga, A.M., Morcillo, A.M., Tresoldi, A.T., Baracat, E.C., Factors associated with infant death after apparent life-threatening event (ALTE) (2010) J Pediatr (Rio J), 86, pp. 515-519Anjos, A.M., Nunes, M.L., The epidemiologic profile of children with Apparent Life Threating Event (ALTE) and prospective evaluation of underlying etiological factors (2009) Rev Bras Saude Mater Infant, 9, pp. 301-309Dewolfe, C.C., Apparent life-threatening event: A review (2005) Pediatr Clin North Am, 52, pp. 1127-1146Gibb, S.M., Waite, A.J., The management of apparent life-threatening events (1998) Curr Paediatr, 8, pp. 152-156Davies, F., Gupta, R., Apparent life threatening events in infants presenting to an emergency department (2002) Emerg Med J, 19, pp. 11-16Shah, S., Sharieff, G.Q., An update on the approach to apparent life-threatening events (2007) Curr Opin Pediatr, 19, pp. 288-294McGovern, M.C., Smith, M.B., Causes of apparent life threatening events in infants: A systematic review (2004) Arch Dis Child, 89, pp. 1043-1048Al-Kindy, H.A., Gélinas, J.F., Hatzakis, G., Côté, A., Risk factors for extreme events in infants hospitalized for apparent life-threatening events (2009) J Pediatr, 154, pp. 332-337de Piero, A.D., Teach, S.J., Chamberlain, J.M., ED evaluation of infants after an apparent life-threatening event (2004) Am J Emerg Med, 22, pp. 83-86Kinali, M., Beeson, D., Pitt, M.C., Jungbluth, H., Simonds, A.K., Aloysius, A., Congenital myasthenic syndromes in childhood: Diagnostic and management challenges (2008) J Neuroimmunol, 15, pp. 201-202Palace, J., Lashley, D., Bailey, S., Jayawant, S., Carr, A., McConville, J., Clinical features in a series of fast channel congenital myasthenia syndrome (2012) Neuromuscul Disord, 22, pp. 112-117Sarnat, H.B., Myasthenia gravis. Disorders of Neuromuscular transmission and motor Neurons (2007) Nelson Textbook of Pediatrics, , Kliegman RM, Behrman RE, Jenson HB, Stanton BF, 18th ed. Philadelphia: SaundersKinali, M., Beeson, D., Pitt, M.C., Jungbluth, H., Simonds, A.K., Aloysius, A., Congenital myasthenic in childhood: Diagnostic and management challenges (2008) J Neuroimmunol, 15, pp. 201-202Engel, A.G., Current status of the congenital myasthenic syndromes (2012) Neuromuscul Disord, 22, pp. 99-111