Introduction: Although a prospective antimicrobial audit and feedback is an effective strategy in an antibiotic stewardship program, previous researchers have not adequately demonstrated a successful impact on patient outcomes. In this study, the causes of fatalities associated with a prospective antimicrobial audit and feedback were analyzed. Methodology: Between June and September 2014, applications for 16 target parenteral formulas (including ceftriaxone, ceftazidime, cefepime, piperacillin/tazobactam, vancomycin, teicoplanin, ertapenem, imipenem/cilastatin, meropenem, levofloxacin, moxifloxacin, ciprofloxacin, tigecycline, linezolid, daptomycin, and amikacin), which were not approved by infectious diseases (ID) specialists, were followed up until patients were either discharged or passed away. Results: Of the 292 cases studied, 193 (66%) were male, with a mean age (standard deviation) of 65.5 (19.3) years. There were five reasons for rejection, including dosage adjustments (37%), no evidence of bacterial infection (28.8%), modifications according to antimicrobial susceptibility (18.8%), target pathogens not being covered (7.2%), and redundant therapy (4.1%). Multiple logistic regression analysis demonstrated that an age greater than 75 years (odds ratio [OR]: 2.58; 95% confidence interval [CI]: 1.32-5.50; p = 0.005) was associated with significant mortality, while urinary tract (OR: 0.26; 95% CI: 0.09-0.70; p = 0.013) and soft tissue/bone infections (OR: 0.18; 95% CI: 0.05-0.61; p = 0.006) were associated with survival. Adjustments according to ID physicians' recommendations were not statistically significant (OR: 0.53; 95% CI: 0.27-1.06; p = 0.074). Conclusions: Antimicrobial adjustments according to ID physicians' recommendations showed only marginally preventative effects against fatalities.