OBJECTIVE: The extent to which modifiable dietary factors may account for some of the variability demonstrated in mammographic density across ethnic groups is unknown. The purpose of this study was to provide pilot data describing the relationship between dietary variables and mammographic density in pre- and postmenopausal Hispanic and non-Hispanic white (NHW) women (N = 238) ranging in age from 41 to 50 years (premenopausal only) or 56 to 70 years (postmenopausal only). DESIGN: Using a cross-sectional design, computer-assisted density assessments were performed on mammograms of both breasts and averaged for analysis. The Arizona Food Frequency Questionnaire was used to estimate dietary intake. RESULTS: Study participants were well educated and overweight, with mean mammographic densities ranging from 20.25% for postmenopausal Hispanic women to 46.94% for premenopausal NHW women. Hispanic women reported higher energy intake than NHW women, but energy-adjusted intake of other nutrients was generally comparable. There was preliminary evidence of ethnic variability in diet-mammographic density associations. Among premenopausal Hispanic women, density was inversely associated with dairy, calcium, and vitamin D intakes (P ≤ 0.05 for all). Among premenopausal NHW women, lower mammographic density was associated with greater intake of vegetables (P ≤ 0.05), and higher density was associated with greater fruit intake (P ≤ 0.05). Among postmenopausal Hispanic women, for every 4.54 increase in the polyunsaturated-to-saturated fat ratio, there was a 9.0% reduction in mammograph density. CONCLUSIONS: These preliminary results suggest that a differential pattern of dietary nutrient associations with mammographic density could potentially exist among Hispanic and NHW women. These ethnic differences in diet and mammographic density associations need to be further explored in larger studies. © 2007 by The North American Menopause Society.