Background: Procalcitonin testing (PCT) demonstrates its effectiveness for specifically diagnosing bacterial infections, as it is elevated in bacterial infections but not viral infections. Its clinical usefulness has been shown with antibiotic selection for different infections. Methods: This retrospective observational study aims to evaluate PCT test clinical utility in reducing the use of antibiotics, and the length of hospital stays. The study conducted at a tertiary hospital in Riyadh, Saudi Arabia included a total of 660 patients who were ordered procalcitonin test. Results: Subjects were grouped according to PCT level. All patients with PCT level ≥ 0.1 ng/ml (n=457) are qualified to receive antibiotic treatments. A total of 75.7% were prescribed antibiotics. The length of hospital stay (LOS) in patients who received antibiotics was statistically significantly higher than patients who did not receive any antibiotics (LOS 32.7 vs. 65.1 days, p-value=0.01). However all patients with PCT level <0.1ng/mL (n=203) show no statistically significant difference in the length of stay at hospital among patients who were prescribed an antibiotic or not (p-value=0.64). Only 31% of this group has inappropriately prescribed an antibiotic. Another infection precursor-like WBC count was also evaluated with no significant differences among groups. Conclusion: This study showed that the utilization of PCT guided antibiotic prescribing reduces the length of stay and reduces antibiotic use. PCT guided antibiotic prescribing can be utilized efficiently in hospital settings.