Maternal diet quality influences birth outcomes. Yet, little research exists that assesses women's diet quality during the first trimester of pregnancy, a crucial time of placental and fetal development. This cross-sectional study, describing diet quality and its relationship with stress, depression, social support, and eating habits in the first trimester, may identify low-income women needing intensive dietary intervention. Seventy-one low-income women completed validated instruments measuring stress, depression, social support, and eating habits; had their height and weight measured; received training on portion-size estimation; and completed three 24-hour dietary recalls (1 weekend day and 2 nonconsecutive weekdays) from July 2009 to February 2010.