Objectives: In this retrospective observational study, the aim is to establish how the implementation of the use of antimicrobial stewardship programs at the hospital and intensive care unit level in a Sucre Clinic in Sincelejo has had a significant impact on the improvement of the rational use of antibiotics, due to the alarming situation of increasing antibiotic resistance. Materials and methods: The methodology used was to analyze the Excel database of the Clinic in such a way as to compare the data from 2017, the period prior to the implementation of the antimicrobial stewardship program (ASP), with the subsequent evolution between the years 2018 and 2022, in relation to the institutional records of four antibiotics—ceftriaxone3, ciprofloxacin4, meropenem5, and vancomycin6, measured in defined daily dose (DDD). Results: According to the defined daily dose values obtained for the four antibiotics, a reduction in the defined daily dose was identified in the post-implementation period. On the other hand, considering the DDD reported by the World Health Organization for each of the antibiotics, significant differences were verified in comparison with those obtained in the clinic in the hospitalization and intensive care unit services. Conclusions: In conclusion, in the clinic, a reduction in the defined daily dose was verified in the period after the implementation of the antimicrobial stewardship program compared to the previous period, both in the hospitalization and intensive care unit, as well as having a mild-to-large effect with Cohen’s D.