Objective: The purpose of this study was to examine the relationship between mental health and sports participation motivation in female students of Islamic Azad University Karaj Branch. Method: This study was a descriptive research that its method was correlation and it was conducted through cross-sectional and survey. Sixty female students (Mage=4/23 ±) were selected as a convenience sample from Islamic Azad University Karaj Branch in all academic levels and in the second semester 2015-2016. The instrument of this study was included a demographic questionnaire, Goldberg's General Health Questionnaire (GHQ), and Gill's Participation Motivation Questionnaire (PMQ). The collected data were analyzed by Pearson's Correlation Coefficient. Results: The results showed that there was a there was a significant relationship between mental health (P=0.05) and social dysfunction (P=0.021) with sports participation motivation in students and students' sports participation motivation increased significantly with the reduction of mental problems and the social dysfunction subscale. Also, there was no significant relationship between depression (P=0.388), anxiety (P=0.425), and somatic symptoms (P=0.199) with sports participation motivation in students and mental health subscales were not a significant predictor for students' sports participation motivation (P=0.198). Conclusions: It is suggested that we can provide a positive effect on students' mental and physical health in the campus and dormitories through the creation of a good atmosphere, desirable learning and training environment, the training place of different sports, counseling centers for the provision of counseling services due to the improvement of mental health, and the holding of workshops.