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Omega-3 fatty acids are essential to health and provide cardio-protective benefits. To estimate omega-3 fatty acid dietary intake, we developed a semi-quantitative food frequency questionnaire (FFQ) and pilot tested its reliability and validity in a convenience sample of cardiac patients in the Midwest. The FFQ was developed using the USDA Nutrient Database for Standard Reference and the ESHA Food Processor, ESHA Research, Salem, Oregon. Three 24-h recalls and two administrations of the FFQ two weeks apart were obtained by a dietitian by phone and home visit from 28 volunteers. Pearson correlation was used to assess the association between food recalls and FFQ. Alpha coefficient was used to assess reliability of the FFQ. The correlation of omega-3 fatty acids intake using the food recalls and FFQ was 0.42 (P<0.05). Reliability of the FFQ was 0.83 with the food categories ranging from 0.93 for grains to 0.57 for vegetables. Ninety percent of omega-3 fatty acid intake was provided by 28 foods, with the top two food sources from plant origin. The FFQ yielded excellent reliability and acceptable validity in the population tested and can be used to estimate total omega-3 fatty acid intake from plant, animal, and seafood sources in the diets of cardiac patients.