In recent years, free fatty acid binding proteins (FABPs) are implicated in spermatogenesis and sperm morphology. FABPs are members of the intracellular lipid-binding protein family; they exhibit tissue specific expression like the FABP9/PERF15 (Perforated15) male germ cell-specific fatty acid linkage-protein.The aim of the study was to assess the levels of seminal FABP-9 in normozoospermic and oligozoospermic men, and the possible relations between seminal FABP-9 levels and semen parameters.Research was carried out on 60 male volunteers who were admitted to Selcuk University Faculty of Medicine of Andrology Laboratory. Normozoospermic individuals (n = 30) were identified as Group 1, and Oligozoospermic individuals (n = 30) were identified as Group 2. The semen samples were collected in sterile plastic containers. Sperm parameters were assessed according to Kruger's criteria. Seminal plasma FABP-9 levels were analyzed by ELISA method. Outcomes were statistically evaluated at 0.05 significance level with SPSS (22.0). The Receiver Operating Characteristic (ROC) curve was used to evaluate the performance of FABP-9 levels as compared to that of the concentration and motility data of the sperm. FABP-9 levels were significantly higher in normozoospermic individuals (3.41 ± 1.64 ng/mL) than in oligozoospermic individuals (1.99 ± 0.78 ng/mL). There were significant correlations between FABP-9 levels and sperm concentration, total sperm count, motility, progressive motility, immobility, Total Progressive Motil Sperm Count (TPMSC), head anomaly, and teratozoospermia index.We suggest that FABP-9 level is an important biomarker, and low levels of semen FABP-9 may impact the fertility status based on the ROC findings.