Inhibition of emotional expression has been associated with the incidence and progression of breast cancer and other chronic illnesses. Others have theorized that it may not be repression itself, but rather ambivalence over the expression of emotions that is the important health-related factor. The Women's Health Initiative (WHI), a long-term, national study focusing on disease prevention among postmenopausal women, is unique in its assessment of expression and ambivalence of negative emotion in a large study sample of multiethnic, older women. Psychological factors such as expression of negative emotion and ambivalence about expression of emotion are also determined by social patterning. The current study examined the psychometric properties of the instruments used to measure each construct and variation across race/ethnicity and age. The analysis suggests that the scales can be used with confidence in diverse ethnic and age groups. Examining ambivalence about expression of negative emotion in future longitudinal research will further elucidate its role in predicting disease incidence and recovery, both important in reducing the public health burden of chronic disease.