Comorbidity, the coexistence of chronic conditions, is commonly found in older populations. A thorough evaluation had not been performed concerning the impact of comorbidity on increasing age. Using data from the Supplement on Aging to the 1984 National Health Interview Survey, an examination of prevalence and patterns of comorbidity in older populations was conducted. Respondents, who were 55 years old or older, answered questionnaires regarding chronic conditions and physical limitations. Other health-related and social issues were also explored. The nine most frequent chronic conditions were identified in individuals over 60-years old. In degree of prevalence they were as follows: arthritis, high blood pressure, cataracts, heart disease, varicose veins, diabetes, cancer, osteoporosis/hip fracture, and stroke. An increase of multiple disorders was associated with advancing age. Most individuals who were 80 years or older had two or more of these nine conditions; 70 percent of the women and 53 percent of the men. Comorbidity was directly associated with the prevalence of any of the nine individual conditions. The number of people who required assistance with normal daily activities also increased with the prevalence of comorbidity. An editorial note from the Centers for Disease Control observed a number of limitations of the data from this survey. Despite these limitations, the incidence of comorbidity in older individuals is substantial and efforts aimed at prevention should be the focus of public health strategies.