OBJECTIVE: To detect the effects of methylphenidate (MPH) and atomoxetine (ATX) on the cerebellum. STUDY DESIGN: Male juvenile rats were separated into MPH, ATX, and control groups. The amount of Purkinje cells and the histological structure of the cerebellum were investigated. RESULTS: In the MPH group a significant increase was noted in the number of Purkinje cells as compared with the other groups. Also, it was observed that the number of Purkinje cells increased in the ATX groups. The histopathological results showed that MPH and especially ATX caused pyknotic nuclei and irregular cell boundaries in some Purkinje cells. CONCLUSION: MPH and ATX can be used to reduce attention-deficit hyperactivity disorder symptoms. We detected that MPH administration caused an increase but ATX caused a decrease in Purkinje cell numbers. Our data provides evidence to answer questions about the effects of MPH and ATX on the cerebellum. At this point, this study will be useful for contributing to the current literature and furthering the research in this field. © Science Printers and Publishers, Inc.