Objective: Marital difficulties can confer risk of coronary heart disease, as in a study of outwardly healthy couples (T. W. Smith et al., 2011) where behavioral ratings of low affiliation and high control during marital disagreements were associated with asymptomatic coronary artery disease (CAD). However, taxometric studies suggest that marital discord is more accurately represented by discrete groups, rather than continuous dimensions. To determine if a categorical representation of marital discord was also related to CAD, discordant and nondiscordant groups were identified via cluster analysis in further analyses of the T. W. Smith et al. (2011) study. Method: One hundred fifty healthy couples (M age = 63.5) completed a marital disagreement discussion, self-reports of anxiety and anger during the disagreement, and self-report measures of marital adjustment. CAD was measured as coronary artery calcification (CAC) via computed tomography scans. Results: In a 2-group cluster solution, 31% of couples were characterized as discordant, with higher levels of hostility and dominance and lower levels of warmth compared with the nondiscordant group. Discordant couples reported lower marital adjustment and greater negative affect during the discussion. Controlling biomedical and behavioral risk factors, discordant couples had greater CAC (p = 0.029, [eta][superscript 2] = 0.035). Discordant and nondiscordant groups defined via self-reported marital adjustment did not differ in CAC (p = 0.17, [eta][superscript 2] = 0.014). Conclusions: Marital discord defined categorically and with behavioral observations was associated with greater levels of asymptomatic CAD. Marital discord is associated with higher risk at early stages of coronary heart disease, but commonly used self-reports may underestimate this risk. (Contains 2 footnotes, 3 tables, and 1 figure.)