This study examined racial/ethnic group differences in depressive symptoms and treatment effect in a diverse clinical sample of post myocardial infarction (MI) patients. Specific aims were to test group measurement equivalence of the Beck Depression Inventory (BDI) across non-Hispanic Blacks, non-Hispanic Whites, and Hispanic cardiac patients and to test stability of a BDI measurement model over time from baseline to six-months post-treatment both in the treatment and the usual care groups. The participants included 2370 diverse post-MI patients (467 non-Hispanic Blacks, 1647 non-Hispanic Whites, and 256 Hispanics), a subgroup of the participants who were clinically depressed and/or socially isolated from the Enhancing Recovery in Coronary Heart Disease (ENRICHD) trial. Depression was measured using the BDI at baseline and six-months post-treatment. A between-group analysis of variance (ANOVA) of the baseline BDI total scores, a series of confirmatory factor analysis of the BDI items, and structural equation modeling of treatment effect on depressive symptoms were conducted to investigate the study aims. Gender, baseline depression levels, baseline antidepressant medication use, education, income, and employment were included as covariates in the model testing for racial/ethnic differences in baseline depression levels and treatment effect on depression symptoms. Findings suggested that racial/ethnic cardiac patients exhibited different cognitive yet similar somatic depression symptoms and that treatment effect on the reduction of depressive symptoms were comparable across racial/ethnic groups. It is essential to distinguish cognitive and somatic depression symptoms among cardiac patients and to develop intervention programs targeted on specific subtypes of depression for treatment. Future investigations should consider the predictive validity and relevance of the BDI subscales with respect to underlying symptoms, treatment aims, and clinical outcomes among cardiac patients and other clinical populations.