Increasing demand to deliver and document therapeutic and preventive care sharpens the need for disease management strategies that accomplish these goals efficiently while preserving quality of care. The purpose of this study was to compare selected outcomes for a new chronic disease management program involving a nurse practitioner - physician team with those of an existing model of care. One hundred fifty-seven patients with hypertension and diabetes mellitus were randomly assigned to their primary care physician and a nurse practitioner or their primary care physician alone. Costs for personnel directly involved in patient management, calculated from hourly rates and encounter time with patients, and pre- and post-study glycosylated hemoglobin (HbA(1c)), high-density lipoprotein cholesterol (HDL-c), satisfaction with care and health-related quality of life (HRQoL) were assessed. Although 1-year costs for personnel were higher in the team-treated group, participants experienced significant improvements in mean HbA(1c) ( - 0.7%, p = 0.02) and HDL-c ( + 2.6 mg dL( - 1), p = 0.02). Additionally, satisfaction with care improved significantly for team-treated subjects in several sub-scales whereas the mean change over time in HRQoL did not differ significantly between groups. This study demonstrates the value of a complementary team approach to chronic disease management in improving patient-derived and clinical outcomes at modest incremental costs.