The purpose of this study was to find out development of social skills of 511 students with mental retardation who were in secondary special schools. The test tool was Paradise Korea Standard Adaptive Behavior Scale. The results indicated that children with mental retardation in the secondary special schools acquired mean of 6.51 out of 24 in the 12 social skill questionnaires. This result means that even though the students with mental retardation who were in secondary special schools are 13-18 chronological years old, their social skill ages are under 6 years old. However their social skills have developed slowly and steadily at the age of 14. Their social skills are very weak in the items of their feeling expression, using email and telephones. These results showed that students with mental retardation in the secondary special schools need more social relationship experiences in their school, home and their local communities with others for their independent vocational life.
Key Words : Mental Retardation, Adaptive Behavior Scale, Social Skills,