Background The co-occurrence of multiple chronic conditions in cancer patients is common and can have negative impact on cancer and cancer survivorship outcomes. This study aimed to document comorbidity occurrence among African-American and Latina (English language preferred (ELP) and Spanish language preferred (SLP)) breast cancer survivors (BCS). Methods Eighty-eight African-American, 95 ELP Latina, and 137 SLP Latina BCS were recruited via case ascertainment from the California Cancer Registry and hospital registries. BCS completed a self-report questionnaire assessing demographic and cancer characteristics, and presence of comorbidities. Results Overall, 75 % of BCS reported at least one comorbidity with arthritis (37 %), high blood pressure (37 %), psychological difficulties (29 %), and diabetes (19 %) being most commonly endorsed. SLP Latinas were more likely to report diabetes (29 %), psychological difficulties (42 %), and >3 comorbidities (p<0.05). Latina BCS were twice as likely to report osteoporosis and headaches compared to African-Americans; while one in two African-Americans reported hypertension and arthritis. Older age was correlated with arthritis, diabetes, glaucoma, high blood pressure, and osteoporosis. Conclusions Our findings suggest that investigating the occurrence of comorbidities across ethnic groups may shed some light in understanding cancer survivorship risk for poor health outcomes and health disparities. Having a better grasp of comorbid conditions may aid in more appropriate early assessment, better follow-up care, surveillance, and management of the cancer and the comorbid condition(s). Implications for Cancer Survivors Integrated control and management of comorbidities among cancer survivors has the potential to improve quality care for the whole person, and increase survival and decrease morbidity.