Aim: The incidence of biliary tract cancer (BTC) is many-fold higher for American Indians (AI) relative to non-Hispanic whites (NHW). Neither gallstones nor genetics can account for this difference. There is speculation that certain fatty acids in bile may play a role in preventing BTC. Since diet may influence composition of bile, we compared the dietary intakes of urban AI and NHW adult women in New Mexico. Methods: Design, a cross-sectional study of the diets of lactating AI and NHW women was conducted. Setting, the University of New Mexico Hospital. Participants, healthy lactating women 18 to 39 years of age were recruited. Main outcome measures, a three-day diet record for each participant was analyzed. Results: The AI women consumed less calcium (p = 0.04) and significantly less short and intermediate chain-length fatty acids (C4-C12), but nearly twice as much proinflammatory arachidonic acid as the NHWs (p <0.01). The intake of dairy products by AI women was less than NHW women (p = 0.01) while the intake of processed meat products was higher (p <0.01). Conclusion: Dietary factors may account for the difference in the risk of BTC between AI and NHW women.