Objective In a racial/ethnically-diverse sample of low-income mothers of children aged 3-6, we determine: 1) whether a regular source of dental care (RSDC), self-rated oral health, beliefs and behaviors differ by racial/ethnic group; 2) estimate whether a RSDC is associated with oral health, beliefs and behaviors, and whether these associations differ by racial/ethnic group; and 3) examine these relationships for mothers’ dental utilization. Basic Research Design Cross-sectional survey. Participants From a population of 108,151 Medicaid children aged 3-6 in Washington state, U.S., 10,909 eligible children were sampled stratified by racial/ethnic group. Eligible mothers completed a mixed-mode survey in the following groups: Black (n=818), Hispanic (n=1,310), or White (n=1,382). Main Outcome Measures Measures were mothers’ RSDC, personal characteristics, self-rated dental health, appearance of teeth, dental problems, brushing duration, flossing frequency, use of toothpicks or whiteners, belief that cleaning prevents cavities or loose teeth, and self-reported services at last dental visit. Results About 38-40% of mothers had a RSDC. For Black, Hispanic and White mothers, having a RSDC was associated consistently with better oral health, greater likelihood of a dental cleaning and less likelihood of tooth extraction. RSDC was not associated generally with oral health beliefs and behaviors. Oral health behaviors differ by racial/ethnic group. Conclusions Relationships between RSDC and self-reported oral health, health behaviors, beliefs and dental services are similar for Black, Hispanic and White low-income mothers of young children. Oral health behaviors differ across racial/ethnic groups, which may have implications for mother and child oral health. Key words: Access, dental care, dental insurance, disparity, Medicaid, mothers, oral health, oral hygiene, race and ethnicity