This study is highly innovative to be the first randomized trial to: 1) evaluate the efficacy of MBSR(BC) among breast cancer survivors for objective neuropsychological and subjective improvements in cognitive functioning; 2) evaluate genetic profiles as moderators of MBSR(BC) on improving CI; 3) offer the MBSR trial in Spanish in addition to English for the purpose of improving cognition; and 4) determine the effect of MBSR(BC) on CT-induced CI among breast cancer survivors related to health service utilization costs.