Objective: The aim of the present study was to investigate the effectiveness of differential reinforcement of incompatible behaviors in reduction of hyperactive behaviors in four students (two boys and two girls) with intellectual disability in a special school setting in Birjand, Iran. Method: The research design was quasi-experimental with single subject and reversal design A-B-A-B and the sample was selected by random sampling method. In this design nine target behaviors have been observed in frequent sessions baseline, treatment intervention and follow up phases and recorded percent of behaviors and charts and visual analysis have been used for data analysis. Results: The results of the study showed that all target behaviors (hyperactivity behaviors) of the partcipants in intervention and follow up phases were reduced dramatically. Conclusion: The findings of the study supported the effectiveness of the differential reinforcement of incompatible behaviors as a treatment method in reduction of hyperactive behaviors in students with intellectual disability.