Objective: To evaluate the clinical and financial impact of clinical pharmacists’ interventions (CPIs) on antimicrobial use at a 500-bed multidisciplinary tertiary care hospital in Oman. Methods: A retrospective analysis of CPIs related to antimicrobials use at Sultan Qaboos University Hospital (SQUH) from January to December 2018. Interventions were recorded using an electronic CPI form and were reviewed by two independent CPs. Data on the type and clinical significance of the interventions were extracted. Cost analysis was done using a previously defined cost avoidance model in addition to direct cost reduction estimation. Descriptive data were used to describe the results. Results: In 2018, 26% of CPIs were related to antimicrobial use, with more than 60% of these interventions done on intensive care unit patients. The most common intervention type was adjusting the dosing regimen (42% of the total interventions), followed by deletion of the antimicrobial order in 34% of the cases. The most common clinical impact of CPIs was improving efficacy in 45% of the interventions, followed by preventing unnecessary exposure to the antimicrobials in around 30% of the interventions. The interventions were of major significance in 64% of the cases. This translated into a projected net cost saving of approximately $200,000 USD/year. Conclusions: CPs interventions on antimicrobial use had a positive impact on both the clinical and financial outcomes.