Rehabilitation of the adult with severe head-injury is of great interest in the clinical community. However, a dearth of data in the literature makes it difficult to evaluate existing rehabilitation programs. This paper provides a cross-cultural validation of one of the most widely cited rehabilitation programs, Institute of Rehabilitation Medicine, New York University. Three groups of adults (n = 10, n = 11, n = 11; average age, 27) with severe head trauma (average duration of coma, 46 days) were enrolled in a comprehensive rehabilitation program while in their chronic stage (average postcoma interval, 59 months). Treatment lasted 30 weeks for each group and included cognitive and perceptual remediation, problem-solving learning, personal counseling, physical exercise and relaxation, social skills, and prevocational training. A quasi-experimental design was used to evaluate the effectiveness of the rehabilitation program. The measures that showed the greatest improvements for the three groups were noted in the psychomotor tests of attention, in visual information processing, memory, and complex reasoning. Most measures of manual dexterity, verbal IQ and basic academic skills did not change. Subjects with motor system damage gained cognitively as much as those whose motor system was undamaged. The improvements noted in the three groups were robust and were evident 3 to 12 months posttreatment.