The UNC Alumni Heart Study (UNCAHS) is a prospective study of the role of psychosocial factors, in particular hostility, in the development of coronary heart disease. The target population is composed of persons who completed the Minnesota Multiphasic Personality Inventory while attending the University of North Carolina in the mid-1960s. Logistic regression analyses were used to determine whether hostility, demographic and other variables were significant determinants of the subjects' locatability and participation. It was found that MMPI hostility scores at initial testing were unrelated to either potential or actual locatability or participation. Thus there is no evidence that hostility is the source of selection bias in the UNCAHS. Selection into the study was predicted by age, sex, degree status and variables concerned with the conditions under which the MMPI was administered. It is concluded that follow-up studies of college cohorts may have study-specific sources of selection bias.