Objective: Semen analysis is considered as a first step in diagnosis and assessment of infertile men. Materials and Methods: This is a case-control study of 42 men with infertility disorders in Ilam western of Iran. Semen analysis was done using Weili dynamic sperm analysis software according to WHO classification. A standard questionnaire was used for collecting demographic characteristics. Results: Based on semen analysis research participants were stratified into two groups. The case group “Oligospermia” with sperm counts of less than 20 million in mL (n=12) and the control group “Nonoligospermia” with values above that cutoff point (n=30). Mean age for cases and controls were 29.1± 4. 5 and 32.4± 5.4 years respectively. Almost all cases (91.7 %) had problems in the class A in which means sperm move ahead slowly. The corresponding rate for the control group was 70.0%. Only 8.3% of case group had normal live ratio (L.R) whilst this rate was 40% in controls. There was a significant difference between cases and controls in terms of family history of infertility disorders (p=0.001). Having a military job was also another significant difference between cases and controls (p=0.001). Conclusion: Early semen assessment in high risk men had a significant role in infertility process and helps to prevent of its severe complications.