Aim: The aim of the present study was to evaluate and compare the effects of short-term and long-term strength training increasingly on neutrophils, lymphocytes and monocytes blood factors in untrained male students Khatam University of Behbahan. Methods: For this purpose, 45 male students between 18-22 years were selected. Subjects were categorized into three groups of 15 subjects randomly. These include a control Group 1, Group 2 with short-term strength training increasingly and Group 3 with long-term strength training increasingly. In order to examine data distribution between groups of Kolmogorov-Smirnov test for equality of variances assumption of intra-group study, Levene’s test was used. To investigate the effectiveness of the practice of paired t-test was used. In a comparison test between the selected parameters in one-way analysis of variance was used for independent samples and to analyze and compare three groups of variables, Tukey test was used. The significance level for all tests was p ≥ 0.05 and statistical analysis was performed using SPSS statistical software. Results: The results showed that after a strength training, mean difference of the variable Neutrophil percentage in training groups and control group in post-test was significant p=0.016. Mean difference of the variable lymphocytes percentage in training groups and control group in post-test was not significant p=0.217. Mean difference of the variable monocytes percentage in training groups and control group in post-test was not significant p=0.114. Conclusion: These results suggest that cell-mediated immunity in young boys is influenced by the intensity and duration of exercise.