Background: Although 1 in 5 adults will develop heart failure (HF) in their lifetime, data on the effect of plasma omega-6 (n-3) PUFAs on risk of HF are currently sparse. Objectives: We investigated whether plasma phospholipid omega-6 concentrations are associated with risk of HF in US male physicians. In a secondary analysis, we evaluated whether such an association differs between HF with and without previous myocardial infarction (MI). Design: With the use of a nested case-control design, this ancillary study comprised 788 cases and 788 matched controls from the Physicians' Health Study. Plasma omega-6 PUFAs were measured by using gas chromatography. Results: The mean age of subjects was 58.7 y with a mean follow-up time of 17.1 y. We did not show any evidence of a statistically significant relation between total omega-6 PUFAs and HF [OR (95% CI): 1.00; 0.85 (0.63, 1.14); 0.84 (0.63, 1.13); and 0.87 (0.63, 1.20) across consecutive quartiles of omega-6 PUFAs; P -linear trend = 0.39]. Results were similar for HF with and without previous MI. Conclusion: Our data showed no significant association between total plasma omega-6 PUFAs and risk of developing HF.