<p>Congenital myotonic dystrophy is the most severe form of inherited myotonic dystrophy, presenting with generalized muscle weakness, breathing problems, and feeding difficulties. We report a patient with congenital myotonic dystrophy who began rehabilitation early in the neonatal intensive care unit. The mother had myotonic dystrophy and experienced no complications during pregnancy. The patient was born at a gestational age of 38 weeks and 1 day, weighing 2712 g, with an Apgar score of 1/4, and was diagnosed with congenital myotonic dystrophy. Marked generalized hypotonia and respiratory compromise were observed from birth, and the patient was orally intubated and managed with a ventilator. Rehabilitation to promote sensory-motor development was started 13 days after birth. Initially, generalized muscle hypotonia and prominent limitation of joint range of motion were observed. Therefore, joint range of motion exercises, positioning, and rehabilitation of the sensory-motor system were conducted first, while monitoring circulatory and respiratory status. After weaning from the ventilator, feeding evaluation was started on the 123rd day of life. In collaboration with physicians and nurses, feeding volume was increased stepwise to safely introduce oral feeding. The infant gradually became capable of oral intake and was discharged from the hospital on the 160th day of life. In this report, we demonstrated that rehabilitation intervention for infants with congenital myotonic dystrophy from the time of admission to the neonatal intensive care unit contributed to improved motor development, initiation of oral feeding, and smooth discharge.</p>