This randomized controlled trial compares the effects of walnuts, fish and the combination of the two on cardiovascular risk factors among overweight or obese females who were losing their weight.Ninety-nine overweight and obese women were randomized to 3 weight-reducing diets: fish (300 g/week), walnut (18 walnuts/per week) or fish + walnut (150 g fish and 9 walnuts /week) for 12 weeks. Anthropometric indices, systolic & diastolic blood pressure, fasting blood glucose, inflammatory markers, serum lipids and coagulating factors were measured.The reduction in systolic blood pressure (SBP) (-5.0 ± 0.3 mm Hg, P = 0.01), fasting blood glucose (FBG) (-12.4 ± 1.9 mg/ dL, P = 0.001), low-density lipoprotein (LDL) (-6.2 ± 1.3 mg/dL, P = 0.03), high-sensitivity C-reactive protein (CRP) (-0.51 ± 0.08 mg/L, P < 0.001), D-dimer (-0.45 ± 0.07 mg/dL, P < 0.001), fibrinogen (-22.4± 4.5 mg/dL, P < 0.001), alanine aminotransferase (ALT) (-6.4 ± 0.9 mg/dL, P < 0.001), aspartate aminotransferase (AST) (-6.3 ± 0.9 IU/L, P = 0.01), tumor necrosis factor-alpha (TNF-α) (-0.08 ± 0.02 ng/mL, P = 0.01), interleukin 6 (IL-6) (-1.6 ± 0.1 ng/mL, P < 0.001) and increase in high-density lipoprotein (HDL) (3.6 ± 0.2 mg/dL, P < 0.001) were significantly higher in the group randomized to the fish + walnut diet compared with either the fish group or the walnut group. A significant decrease was seen in TG (-7.3 ± 1.1 mg/dL, P < 0.001) and diastolic blood pressure (DBP) (-2.0 ± 0.06 mm Hg, P = 0.01) levels in the fish group and the walnut group compared with the fish + walnut group. The change in other risk factors was not different among groups.The present study shows that the combination of marine and plant omega-3 together is more effective on blood pressure levels, fasting blood glucose, inflammatory markers, serum lipids and coagulating factors than the fish or walnut in isolation.