Social isolation has been linked to a variety of adverse health outcomes, including cardiovascular disease. Researchers have attributed this association to the feelings of loneliness that accompany social isolation, but they have rarely assessed loneliness directly. In a sample of 180 older adults, feelings of loneliness and two kinds of social deficits that underlie loneliness--limited emotional support and limited companionship--were examined in relation to the likelihood of having a coronary condition. Potential physiological, behavioral, and affective mediators were examined as well. Greater loneliness was found to be associated with an increased probability of having a coronary condition, as were low levels of both emotional support and companionship. Mediators of these links were not identified, however, in this sample. These results underscore the value of examining the specific social deficits that underlie loneliness in investigations of the relation between loneliness and cardiovascular health in later life.