Correct dosing of antimicrobial drugs in septic patients receiving continuous renal replacement therapy (CRRT) is complex. This study aimed to evaluate the effects of dosing adjustments performed by pharmacists on the length of intensive care unit (ICU) stay, ICU cost, and antimicrobial adverse drug events (ADEs). A single-center, 2-phase (pre-/post-intervention) study was performed in an ICU of a university-affiliated hospital. Septic patients receiving CRRT in the post-intervention phase received a specialized antimicrobial dosing service from critical care pharmacists, whereas patients in the pre-intervention phase received routine medical care without involving pharmacists. The 2 phases were compared to evaluate the outcomes of pharmacist interventions. Pharmacists made 183 antimicrobial dosing adjustment recommendations for septic patients receiving CRRT. Changes in CRRT-related variables (116, 63.4%) were the most common risk factors for dosing errors, and β-lactams (101, 55.2%) were the antimicrobials most commonly associated with dosing errors. Dosing adjustments were related to a reduced length of ICU stay from 10.7 ± 11.1 days to 7.7 ± 8.3 days (p = 0.037) in the intervention group, and to cost savings of $3525 (13,463 ± 12,045 vs. 9938 ± 8811, p = 0.038) per septic patient receiving CRRT in the ICU. Suspected antimicrobial adverse drug events in the intervention group were significantly fewer than in the pre-intervention group (19 events vs. 8 events, p = 0.048). The involvement of pharmacists in antimicrobial dosing adjustments in septic patients receiving CRRT is associated with a reduced length of ICU stay, lower ICU costs, and fewer ADEs. Hospitals may consider employing clinical pharmacists in ICUs.