Stereotypic behavior is defined repetitive behaviors observed various types of developmental disorders, especially in autism and is also a discriminative criterion to diagnose the autism. Various procedures have been used to reduce the stereotypic behaviors in individuals with these behaviors. The purpose of this study is to investigate the procedures' effectiveness about reducing the stereotypic behaviors. A total of 18 studies were examined published in between 1996 and 2010 about reducing vocal stereotypy, motor stereotypy or both of them. Descriptive and meta-analysis were carried out on these studies. Whereas results of descriptive analysis revealed that the examined procedures are effective to reduce the stereotypic behaviors, results of meta-analysis showed that these procedures are "uncertain".