Data from three different sources of periodontal patients were collected and examined to find if there was a significant difference between these groups relative to the prevalence of medical problems. Data were evaluated to show if age and sex were significantly related to the existence of medical problems and to determine which problems were the most prevalent. A total of 581 periodontal patients' records were obtained. Results of the evaluation showed that the private office group had 27.6% medical problems, the academic dental center had 46.3%, and the hospital dental clinic had 74.1%. Cardiovascular disease was the most prevalent medical problem in all groups and orthopedic disease or injury was second. Within each group, sex was not significantly related to the presence of a medical problem. Age was a highly significant factor, with the prevalence of medical problems increasing with advancing age.