Older adults are demanding increased healthcare attention with regards to prescription use due in large part to highly complex medication regimens. As patients age, medications often have a more pronounced effect on older adults, negatively impacting patient safety and increasing healthcare costs. Comprehensive medication reviews (CMRs) optimize medications for elderly patients and help to avoid inappropriate medication use. Previous literature has shown that such CMRs can successfully identify and reduce the number of medication-related problems and improve acute healthcare utilization. The purpose of this pharmacy resident research study is to examine the impact of pharmacist-conducted geriatric medication reviews to reduce medication-related problems within a leading community health system in southwest Michigan. Furthermore, the study examines type of pharmacist interventions made during medication reviews, acute healthcare utilization, and physician assessment of the pharmacist’s value. The study was conducted as a retrospective post-hoc analysis on ambulatory patients who received a CMR by a pharmacist at a primary care practice. Inclusion criteria included patients over 65 years of age with concurrent use of at least five medications who were a recent recipient of a CMR. Exclusion criteria included patients with renal failure, or those with multiple providers involved in primary care. The primary outcome was the difference in number of medication-related problems, as defined by the START and STOPP Criteria (Screening Tool to Alert doctors to Right Treatment/Screening Tool of Older Persons’ Prescriptions). Secondary outcomes included hospitalizations, emergency department visits, number and type of pharmacist interventions, acceptance rate of pharmacist recommendations, and assessment of the pharmacist’s value by clinic providers. There were a total of 26 patients that received a comprehensive medication review from the pharmacist and were compared to a control group, patients that did not receive a CMR. The average patient age for both groups was 76 years old. A total of 11 medication-related problems in the intervention group patients were identified compared with 24 medication-related problems in the control group (p-value 0.002). Pharmacist-led comprehensive medication reviews were associated with a statistically significant different in the number of medication-related problems as defined by the START and STOPP criteria.