Introduction: The aim of this study was to investigate the effects of acute and chronic administration of Ritalin on some behavioral parameters such as anxiety and locomotor activity and its comparison between male and female rats. Method: The present study is an experimental interventional study performed on 40 adult rats. Rats were divided into 8 groups (5 Rats per group); including two control groups and six treatment groups. Control groups were given saline and treatment groups were given therapeutic doses or high doses Ritalin per day for 30 days by gavage. The effects of the drug on anxiety and locomotor activity were monitored by Elevated Plus Maze and Open Field respectively. Data were analyzed by one-way ANOVA and Duncan’ s test using SPSS software. Results: In the chronic test, the number of line crossing significantly was increased in the both genders of 10 mg/kg. Meanwhile, the data showed no significant change in the rate of anxiety subsequent to the acute or chronic Ritalin administration. It is worth mentioning that female rats in high dose showed less anxiety comparison to male counterparts. Conclusion: This study revealed that long-term use of high dose of Ritalin may lead to increasing locomotor activity and then behavioral sensitization in both sexes. Furthermore, Ritalin has no impact on anxiety rate in therapeutic doses.