Background: Self-perceived lactose intolerance may result in adverse dietary modifications; thus, more studies are needed to understand the prevalence of self-perceived lactose intolerance and how it relates to calcium intake and selected health conditions. Objective: The objective was to examine the effects of selfperceived lactose intolerance as it relates to calcium intake and specific health problems that have been attributed to reduced intakes of calcium and dairy foods in a nationally representative multiethnic sample of adults. Design: This was a cross-sectional study in a national sample of 3452 adults. The relation between self-perceived lactose intolerance, calcium intakes, and physician-diagnosed health conditions was analyzed by using linear regression analyses. Results: Of the total sample, 12.3% of respondents perceived themselves to be lactose intolerant. The age-adjusted prevalence of self-perceived lactose intolerance was 7.8% for non-Hispanic whites, 20.1% for non-Hispanic blacks, and 8.8% for Hispanics. Respondents with self-perceived lactose intolerance had significantly lower (P < 0.05) average daily calcium intakes from dairy foods than did those without self-perceived lactose intolerance. A significantly higher (P < 0.05) percentage of respondents with self-perceived lactose intolerance than of respondents without self-perceived lactose intolerance reported having physician-diagnosed diabetes and hypertension. The odds of self-reported physician-diagnosed diabetes or hypertension decreased by factors of 0.70 and 0.60, respectively, for a 1000-mg increase in calcium intake from dairy foods per day. Conclusions: Self-perceived lactose-intolerant respondents had a significantly lower calcium intake from dairy foods and reported having a significantly higher rate of physician-diagnosed diabetes and hypertension. © 2011 American Society for Nutrition.