Objective: To determine whether a food frequency questionnaire (FFQ) can detect changes in dietary intake before pregnancy to mid-pregnancy relative to a 4-day food record. Design: FFQs and 4-day, weighed food records (4DRs) were completed during similar time intervals before pregnancy and again near mid-pregnancy by women served by a large health maintenance organization in the Minneapolis-St Paul, Minn, area. The outcome of interest was change in the intake of energy and 16 nutrients. Participants were members of the Diana Project, a prospective study of relationships among prepregnancy and pregnancy nutritional and other exposures and reproductive outcomes. Fifty- six (51%) of the eligible women completed the study. Subjects: Well-educated, healthy, white women. Statistical analyses performed Spearman rank order correlations. Results: Mean energy and nutrient intake levels estimated rising the 4DR were generally higher than those estimated using the FFQ. Correlations between change in energy and nutrient intakes measured by the 4DR and FFQ ranged from .75 for vitamin C to .02 for cholesterol and averaged .48. Applications: Comparisons with 4DRs indicate that the FFQ used in this study is appropriate for obtaining reliable estimates of prepregnancy to mid- pregnancy changes in intake of energy and a number of nutrients in similar groups of women.