Personality, psychosocial, demographic and medical variables have been identified as correlates of adjustment to breast cancer and quality of life (QoL). Most studies have examined relationships between personality, social support and adjustment to cancer in predominantly middle-class Caucasian samples, thus limiting the generalizability of their findings. Eighty-one female outpatients at a medical oncology breast clinic in a county general hospital serving primarily indigent Hispanic and African-American patients completed measures assessing demographic and medical information, health-related QoL, cancer-specific distress, mood disturbance, dispositional optimism and satisfaction with social support. Older age, receipt of treatment and greater optimism accounted for 41% of the variance in emotional well-being (p<0.01). Absence of family history of breast cancer, receipt of treatment and optimism accounted for 43% of the variance in functional well-being (p<0.01). Optimism and satisfaction with social support accounted for 43% of the variance in social/family well-being (p<0.01). Absence of treatment (not yet treated) and pessimism accounted for 31% of the variance in cancer-specific distress (p<0.01). Finally, family history of breast cancer and pessimism accounted for 48% of the variance in mood disturbance (p<0.001). Family history of breast cancer and pessimism were related to mood disturbance (p<0.001). No between-group differences were found for race/ethnicity for any of the variables. Encouraging positive expectations and facilitating social support may help women in public sector medical settings cope with the stressful demands of diagnosis and treatment of breast cancer regardless of race/ethnicity. Copyright © 2005 John Wiley & Sons, Ltd.