Autism is characterized with an abnormality of reciprocal social relatedness and of communication development. Also, autistic children show repetitive and stereotypical behavior pattern and deficiency of endurance against change. Dental problems related to autism are self-injury and trauma from accidents. Sometimes self-injury is due to discomfort resulting from restoration and local anesthesia. Also, gingivitis and multiple caries are common because of poor oral hygiene. Autistic children are anxious about visual and auditory stimuli because they don't understand the dental procedure. If the face of any changes in their daily life, their behavior becomes uncontrollable. In a setting such as the outpatient office, an autistic child's uncontrollable behavior makes it difficult to carry out proper treatment. If they need treatment under general anesthesia, it is very difficult to manage them in a ward as they are severly anxious about being admitted to a hospital. Therefore it is necessary to treat these children according to a specific management program under general anesthesia in an outpatient office. This case study reports of a 14 year old autistic teenager who although became uncontrollable because of the pain from multiple caries and from anxiety of the dental treatment eventually received treatment under general anesthesia and under conscious sedation in an outpatient office.