Aim and Background: The main purpose of this study was to review the effectiveness of applied behavioral ANALYSIS (ABA) approach on symptoms of autistic children during a five-year period.Methods and Materials: In this quasi-experimental study, 20 autistic children (3-7 years of age) were intervened by ABA approach at Isfahan Center of Autism for a period of five years (2007-12). Gilliam Autism Rating Scale (GARS) was filled out at baseline and at the end of the five-year period. Besides, the subjects were assessed by a checklist including cognitive comprehension, mathematical and verbal skills, and self-help at the beginning of the study and at the end of each year. After five years, all collected data was analyzed with SPSS19.Findings: Pretest and the posttest values of stereotypic behaviors, communication problems, social interactions, and GARS total scores were significantly different (P<0.001). Furthermore, significant improvements in cognitive comprehension, mathematical and verbal skills, and self-help were observed after each year and at the end of the five-year period (P<0.001).Conclusions: On the whole, it can be concluded that ABA-based interventions can effectively reduce symptoms of autism and increase skills.