Background and Objective: Omega-3 Supplementation has different effects on the body. Terefore, this study was carried out with the aim of investigating the effect of 4 weeks of flaxseed extract supplementation on serum concentrations of Brain-derived neurotrophic factor (BDNF) and C-reactive protein (CRP). Methods: In this double-blind study, 24 male students (mean age, 23.21±1.98) were randomly divided into two groups, including flaxseed extract (n=12) and placebo (n=12). After 4 weeks of supplementation with flaxseed extract, serum levels of BDNF and CRP was measured in fasting state. BDNF level was measured using an enzyme-linked immunosorbent assay (ELISA) kit, and CRP level was measured using an immunoturbidimetric assay kit. Data were analyzed using t-test. The level of significance was set at p<0.05. Results: After four weeks of supplementation with flaxseed extract the mean serum level of BDNF significantly increased (p<0.001), but no significant change was observed in the serum level of CRP (p<0.591). Conclusion: It seems that supplementation with flaxseed extract through increasing BDNF level is useful for the improvement of cognitive and functional benefits of the brain.