In this study, it was determined whether the IL-10 -1082, IFN-gamma +874, and TNF-alpha -308 polymorphisms were associated with suicidal behavior. One hundred forty five patients with suicidal behavior and 160 normal individuals were genotyped for IL-10 -1082, IFN-gamma +874, and TNF-alpha -308 polymorphisms using ASO-PCR method. TNF-alpha -308 G/G genotype has been increased in males with completed suicide behavior versus control group (p value = 0.017). IL-10 -1082 A/A genotype is higher in both male and female suicide completed groups (p value = 0.017). IFN-gamma (+874) A/A genotype was significantly higher in males with completed suicide behavior versus normal male control (p value = 0.027). It can be concluded that IL-10, IFN-gamma, and TNF-alpha polymorphisms may play a role in suicidal behavior.