An ambulatory senior health clinic was developed using the chronic care model (CCM), with emphasis on an interdisciplinary team approach. To determine the effect of this care model approach in a nonprofit healthcare system, an observational, longitudinal panel study of community-dwelling Medicare beneficiaries was performed to examine the effect on physical function and health-related quality of life (HRQL). Participants in the study were recruited from a community sample of 6,864 eligible Medicare beneficiaries. Informed consent and baseline data were obtained from 1,709 individuals (recruitment response rate=25%) and complete data across 30 months from 1,307 (completion response rate=76%). Participants receiving care in the CCM-based senior healthcare practice (n=318) were compared with patients of primary care physicians supported by care managers (n=598) and a group without care managers (n=391). Self-reported data were collected over the telephone to measure physical function and HRQL at baseline and 6, 18, and 30 months. A multiple group mixture growth model was used to analyze physical function and HRQL across the 30 months. Physical function and HRQL mean scores decreased across time in all participants and were moderately correlated at each wave (correlation coefficient=0.74-0.79). Two latent growth classes were identified. In class 1, physical function decreased, and HRQL remained stable across time. In class 2, physical function and HRQL decreased in parallel. Ninety-seven percent of intervention group patients were in class 1, and 99% of patients in comparison groups 1 and 2 were in class 2. Despite physical function decline, patients in a senior health clinic care model maintained HRQL over time, whereas patients receiving traditional care had physical function and HRQL decline. An interdisciplinary team CCM approach appears to have a positive effect on HRQL in this population.