Mailed food records have been suggested as a means to acquire useful food intake data from a large number of participants with minimal effort. The purpose of this cross-sectional study was to explore whether education level and weight status of midlife women affected adequacy of information about dietary intake derived from a self-administered mailed 1-day food record. Adequacy was defined as the ability to describe and record intake with sufficient detail for entry into a computerized diet analysis program without missing data. From October 2007 through March 2008, 100 women (49±5 years), recruited by education level, were mailed a food record booklet and a 16-page actual-size two-dimensional food model booklet with instruction to describe foods, amounts consumed, and preparation methods/recipes. Women returned the completed food record booklet by mail. Between 3 and 13 days later, a registered dietitian called the participants to review missing details, clarify amounts, and probe for omissions. Six categories of missing data included: "omission of portion size," "inaccurate portion size," "insufficient description of portion size," "insufficient description of food," "omission of ingredients," and "insufficient or no preparation method." The percentage of foods with missing data did not differ by education level; however, higher percentages of missing data regarding "insufficient description of food," were observed in obese compared to overweight women. Adequacy of information from the mailed food record was dependent on weight status but not education level. Additional study is needed to determine how to revise instructions for mailed food records in future studies according to weight status of midlife women.