Background Patients with mild mental retard (MR) exist problems of intelligence and life adaptation. MR may be divided in to several subgroups, and mlld MR was much more common (85%). According to guideline from American Association of Mental Retardation (AAMR) and Diagnostic and Statistical Manual of Mental Disorders-IV TR (DSM-IV TR), mild MR was defined an IQ between 50-75. The mild MR was viewed as being trainable and capable of living independently; however, help may be necessary under stress. Some research indicated that among MR patients, cognitive function highly correlated with community self-sufficiency. We suspected that cognitive function may improve after support and vocational training, and community self-sufficiency of these patients improve too. We report an adult patient, with mild MR, having improved IQ under highly supportive environment with persisting occupational training. Case report The patient was a 41 year-old male, who incomplete his courses of high school study. The academic performance and interpersonal interaction were poor since his childhood. He finished his military service under supervising. He tried several jobs but he had difficulty to competence and peer relation. Family reported that he had long-term problems about learning, verbal expression, and emotional inability. He initially consult psychiatric clinic at his age of 39, and mild MR was confirmed (IQ 69). Later patient worked in a sheltered institute, with necessary supervising and support. Now he had more competence to his occupation, and emotion was more stable. He was also regularly followed up at psychiatric clinic, and IQ exam showed an improving result (FIQ:65 to 73) after a 3-year follow-up. Discussion Patient worked in a highly supportive environment, with full interpersonal interaction. The exam showed that the cognitive function was improving, especially in the item of visual attention, visual organization and psychomotor ability. In this case, we observed that education and support do benefit to cognition function, IQ score, and adaptation.