OBJECTIVES: The elderly are vulnerable to adverse drug outcomes due to aging, multiple chronic illnesses and inappropriate use of polypharmacy. The aim of this research was to evaluate the outcomes of a collaborative service performing pharmacist-physician medication therapy management (PP-MTM) model for polypharmacy elderly in Taiwan. METHODS: A randomized, controlled intervention study was designed and implemented in China Medical University Hospital (CMUH), a 2000-bed academic medical center, in Taiwan. We recruited those loyal, polypharmacy elderly patients, who regularly visited more than one medical specialty and possess more than three chronic diseases in the outpatient departments. While patients in the intervention group received continuous, pharmacist-initiative medication therapy management of PP-MTM model for one year, patients in the control group received usual care and follow-up assessment (UC group). The collaborative care in PP-MTM group was provided through reviewing medication-related problems continuously by clinical pharmacist and discussing further with the clinical physician team. The following outcomes were assessed: 1) economic: medical expenditure in CMUH; 2) clinical: lipid, kidney profiles, depression scores; and 3) humanistic: Bathal index, scores of instrumental activities of daily living and EQ-5D scores. The changes of outcomes from baseline to the end of implantation among two groups were compared using inferential analyses. RESULTS: Of 1200 potential patients, 178 elderly patients were involved. Although PP-MTM group had higher proportion of diabetics than UC group (46% vs. 25%), the other demographics and outcomes were comparable at baseline. Over one-year implementation, the PP-MTM group spent $86,480 USD less than UC group. While the changes of clinical and humanistic outcomes in the PP-MTM group were preferable on the extent, there were no statistically significant differences among two groups. CONCLUSIONS:  The implementation of the collaborative PP-MTM model in the outpatient departments was economically beneficial to the polypharmacy loyal elderly patients.