OBJECTIVE: To describe the cost savings achieved in HMO sponsored primary care-based case management and disease management programs in asthma, diabetes mellitus and congestive heart failure (CHF). METHODS: Continuously enrolled participants’ total per member per month (PMPM) charges for medical services one year prior and one year after entry into HMO sponsored case management and disease management programs were compared during fiscal year January 1, 1998 to March 31, 2000. The HMO sponsored programs recruited patients in the primary care setting and relied on clinical guidelines and HMO employed patient education nurses and case management nurses. This initiative is based in 55 primary care sites serving 295,000 insureds across northeastern and central Pennsylvania in the United States. RESULTS: 327 patients with asthma had baseline PMPM of $311, which dropped to $274 PMPM after entry. In diabetes, 3,953 patients had a baseline PMPM of $468 that dropped to $434. The baseline PMPM dropped from $1,748 to $1,402 for 870 patients with CHF. For 965 patients receiving case management, the baseline PMPM was $1,074 and it dropped to $887. Total reductions in claims over one year for each program was $112,524, $1,264,052, $2,587,068 and $1,516,784, respectively with a total reduction in health care claims of $5,480,428. CONCLUSION: While these claims data may be limited by a lack of statistical significance and by regression to the mean, they suggest that case management and disease management programs in asthma, diabetes and congestive heart failure may be able to achieve significant financial savings compared to baseline levels of utilization.