Polypharmacy in older adults causes problems such as increased adverse drug reactions, overdose or duplication, and poor medication adherence. We have established a “medication review team” organized by pharmacists. This prospective and retrospective observational study evaluated the effectiveness of the pharmacist-led team-based approach for reducing polypharmacy as compared to the individual pharmacist approach. Data on the individual pharmacist approach were collected retrospectively, but prospectively for the pharmacist-led team approach. The study included patients who were admitted to the nephrology, orthopedic surgery, and psychiatry wards. Characteristics for patient included in each study group were adjusted using the propensity score method. The pharmacist-led team approach had a significantly higher medication change rate compared to that of the individual pharmacist approach (odds ratio (OR), 2.28; 95% confidence interval (CI), 1.21 to 4.46; p = 0.009). The rate of patients with two or more medication discontinuations and the rate of patients with intervention by young clinical pharmacist were also significantly higher in the pharmacist-led team approach (OR, 2.19; 95% CI, 1.06 to 4.74; p = 0.03 and OR, 5.67; 95% CI, 1.22 to 53.15; p = 0.02, respectively). The rate of patients with discontinuation of potentially inappropriate medications was not significantly different between the two groups (OR, 2.07; 95% CI, 0.86 to 5.33; p = 0.11). Our results suggest that it is possible to improve the quality of medication review by conducting team conferences even with only pharmacists.