Four infant monkeys underwent somatosensory deafferentation of both forelimbs within hours after birth. Ambulation, climbing, and reaching toward objects developed spontaneously in each case. Thumb-forefinger prehension could be trained by operant shaping methods. Two infants deafferented at birth and blinded by eyelid closure were retarded in motor development by only 1 to 2 weeks. Results indicate that topographic sensory feedback and autogenetic spinal reflexes are not necessary after birth for the development of most types of movement performed by the forelimb musculature in monkeys.