Background: Although increasing decisional involvement has been identified as a mechanism for reducing disparities in breast cancer treatment outcomes and improving the quality of care, little is known about these issues from the Latina perspective. Purpose: To evaluate Latina breast cancer patient perspectives about involvement in and informed decision making for surgical breast cancer treatment. Methods: 2030 women with non-metastatic breast cancer diagnosed from 8/05-5/06 and reported to the Los Angeles metropolitan SEER registries were mailed a survey approximately 7 months after surgical treatment. Latina women were over-sampled using a surname methodology developed by the U.S. Census. We report preliminary results on an 82% sample (N=1106). We evaluated ethnic differences in four outcomes related to the surgical treatment decision: involvement in the treatment decision, concordance between actual and preferred amount of involvement, decision satisfaction and decision regret. Independent variables included patient race/ethnicity (Latina-Spanish speaking, Latina-English speaking, African American, Caucasian), age, education, health literacy and clinical variables (tumor behavior, size and histology). Decision outcomes were categorized into dichotomous or 3-level outcomes and multivariate regression used to evaluate correlates of each decision outcome. Results: Approximately 28% of women in each ethnic group reported a surgeon-based, 33% a shared, and 38% a patient-based surgery decision. Spanish speaking Latinas were more likely to report wanting more involvement in the decision than any other ethnic group (P<0.001). All minority groups were less likely than white women to have high decision satisfaction (P<0.05). Spanish speaking Latina women were least likely to have high decision satisfaction and most likely to have high decision regret (P<0.001). Low health literacy was associated with low satisfaction and high regret. Multivariate analyses confirmed an independent effect of Latina race/ethnicity, low education and low health literacy on poor decision outcomes (P<0.05). Conclusions: Latina women face challenges in making informed breast cancer treatment decisions. Future research should explore the interplay between race/ethnicity, education and health literacy. Interventions to reduce disparities in breast cancer outcomes may need to be tailored to ethnicity and degree of acculturation.