The purpose of this study was to examine low-income mothers' perceptions of their children's height and weight in relation to actual measures, and perceptions of dietary quality and health status. Demographic, anthropometric, and dietary quality/health status data were collected during a multi-phase nutrition research project with low-income Minnesotans, and a sub-set of non-pregnant mother-child dyads (mothers ages ≥ 18 years, children ages 9-13 years) were analyzed (n = 257). Participants were Caucasian, African American, American Indian, Hispanic, Asian, or Other/mixed race, and most were homeless. Relationships between maternal perceptions of their child's height and weight and the actual measures, and maternal perceptions of dietary quality and health status for the dyad, were examined using independent and paired samples t-tests, ANOVA, and paired samples correlations. Comparisons were also made by maternal and child body mass index (BMI) status and living situation. Mothers significantly underestimated their child's height and weight (-4.8 ± 13.9 cm, P = 0.000; -5.3 ± 8.5 kg, P = 0.000); greatest misperceptions of weight were among mothers of overweight/obese children (P = 0.000). Mothers not reporting estimates of their child's height and weight (n = 53) had higher BMIs (P = 0.029), and their children were younger (P = 0.000) and lighter (P = 0.021) compared to mothers who provided estimates. Inability to objectify children's weight status may contribute to the obesity epidemic affecting low-income minority populations. Underestimation of weight status may be influenced by cultural perceptions of body image and socioeconomic status.