A 2280 g female infant was born by cesarean delivery at 31 weeks of gestation to a 27-year-old mother with MG. Baby was shifted to newborn intensive care unit for hypotonia, tachypnea, and intercostal retractions starting after birth. The physical examination and chest X-ray were consistent with respiratory distress syndrome. The baby received exogenous surfactant (beractant 100 mg/kg) and was ventilated on synchronized intermittent mandatory ventilation mode. Neostigmine test was performed on the baby to facilitate separation of the baby from mechanical ventilator as her mother was known to be having MG. The test result was positive. Therefore, neostigmine treatment (0.01 mg/kg/h) began at 41st hour of hospitalization. The baby's abdomen distention developed at 56th hour of hospitalization. The finding of direct abdomen X-ray was consistent with intestinal perforation [Figure 1]. A colostomy was performed. Neostigmine was stopped as its effects in increasing risk of intestinal perforation were known. Pathology result was consistent with spontaneous intestinal perforation. No serious complication developed afterwards and the patient was extubated on her 19th day of hospitalization. The patient was discharged with full recovery after her general condition improved on the 35th day of hospitalization. Transient neonatal myasthenia gravis (MG) is observed in babies born to mothers with MG. Hypotony and respiratory distress are the most important warning signs observed in these babies. Anticholinesterases are used in the treatment. In this study, we present a case diagnosed with transient neonatal MG that has developed intestinal perforation after neostigmine treatment.