Purpose: To investigate changes in periodontal parameters and superoxide dismutase activity after root surface debridement with and without omega-3 fatty acid (omega-3 FA) supplementation in postmenopausal women. Materials and Methods: Fifty postmenopausal women with chronic periodontitis were divided randomly into two groups. Group 1 (control group, n = 25) patients were provided with periodontal treatment in the form of scaling and root planing (SRP) plus soft gelatinous capsules containing only some olive oil, while group 2 (n = 25) received SRP along with systemic administration of omega-3 FAs in the same soft gelatinous capsules. Clinical parameters and superoxide dismutase (SOD) activity in the gingival crevicular fluid were recorded at baseline, 3 and 6 months after therapy. Results: By the end of the study period, the omega-3-treated group achieved a greater mean probing pocket depth reduction, a mean gain in clinical attachment level especially in deep periodontal pockets, as well as a greater increase in SOD activity (p 0.01) compared to SRP alone. Conclusions: Adjunctive omega-3 FAs supplements with SRP reduce periodontal inflammation and improve the status of systemic enzymatic antioxidants in postmenopausal women. Keywords: chronic periodontitis, omega-3 fatty acids, scaling and root planing