Introduction:The aim of this study was to evaluate the effect of 12 week concurrent endurance-resistance training on serum testosterone levels and sexual function indices in men over 50 years of age. Material and methods: In this quasi-experimental study, the statistical sample consisted of 29 men with average weight of 81.1 ± 6.7 kg and body mass index of 26.4 ± 1.4 kg/m2 , randomly divided into two control group (n = 12) and training group (n = 17). The training group performed concurrent training (endurance-resistance) for 12 weeks. Serum testosterone levels, cardiopulmonary endurance (VO 2 max), muscle strength and body composition were measured before and after training. Data were analyzed using covariance analysis (ANCOVA) (p < 0.05). Results:Concurrent training in the training group significantly increased serum testosterone levels compared to the control group (p = 0.001). Concurrent training also increased sexual function in the areas of orgasmic performance (p = 0.010) and total score (p = 0.004) in the concurrent training group compared to the control group. Training signifi-cantly decreased fat mass (p = 0.046) and the ratio of waist to hip circumference (p = 0.024) also significantly increased VO2 max (p = 0.001), mean relative muscle strength (p = 0.001) and lean body mass (p = 0.001) in the training group compared to the control group. Conclusions:In general, based on our findings, it seems that training along with increasing serum testosterone levels increases sexual function in the areas of orgasm function and the total score in men over 50 years.