OBJECTIVE: We investigated the association between functional health literacy and markers of pregnancy preparedness in women with pregestational diabetes. RESEARCH DESIGN AND METHODS: English- and Spanish-speaking pregnant women with pregestational diabetes were recruited. Women completed the Test of Functional Health Literacy in Adults (TOFHLA) short form and a questionnaire. A TOFHLA score of < or =30 was defined as low functional health literacy. RESULTS: Of 74 women participating in the study, 16 (22%) were classified as having low functional health literacy. Compared with women with adequate health literacy, those with low health literacy were significantly more likely to have an unplanned pregnancy (P = 0.02) and significantly less likely to have either discussed pregnancy ahead of time with an endocrinologist or obstetrician (P = 0.01) or taken folic acid (P = 0.001). CONCLUSIONS: The results of this study suggest that low functional health literacy among women with pregestational diabetes is associated with several factors that may adversely impact birth outcomes.