It is usually held that most individuals with childhood autism have poor prognosis. According to our knowledge, a favorable outcome of a child with childhood autism is quite rare and inspires a number of controversies. A 4-year-old boy was diagnosed with childhood autism and mild mental retardation. Interviews and findings reported by other specialists were used in the diagnosis and follow-up that lasted for five years, along with parental counseling and therapy. After three years, regression of the symptoms of childhood autism and loss of the criteria for mental retardation were observed. The difference between the second and first examination was 30 and 24 IQ points. The boy attends regular school with individual approach. Childhood autism and mental retardation should not be viewed as static conditions. Early and intensive therapy is recommended. Some children that make good progress can attend regular school.