Studies of the association between type A behavior and coronary heart disease have yielded inconsistent findings. A possible explanation for these inconsistent findings is that type A behavior is simply a marker for other behaviors that are truly related to coronary heart disease. Hostility is one such behavior that has been found in several recent studies to predict coronary heart disease and coronary atherosclerosis; however, several other studies have found null results. In the present study, the predictive power of hostility was tested in a study population of hospitalized men (n = 118) and women (n = 40) scheduled for coronary angiography. Potential coronary risk behaviors were assessed in the angiography patients and they were given the type A Structured Interview. Hostility was measured with the Cook-Medley Hostility Inventory and the Behavior Pattern Hostility Index, a measure of hostility derived from the type A Structured Interview. No significant positive associations were found for either Cook-Medley hostility or behavior pattern hostility and coronary occlusion. This was true whether hostility or coronary occlusion was treated as a dichotomous variable or as a continuous variable. In fact, most of the observed associations were opposite to the predicted direction, although none was statistically significant. Replicating cutpoints of the Cook-Medley Hostility Inventory used in other studies that have reported positive associations with coronary heart disease also yielded null findings. The association between hostility and coronary occlusion was slightly modified by age and sex, but the interaction coefficients were not significant. The sample size yielded adequate statistical power to detect the hypothesized associations, and there was no evidence that selection bias, measurement error, or unexamined confounding accounted for the null findings. These results failed to confirm some earlier reports showing a positive association between hostility and coronary artery disease.