The study determined the impact of antimicrobial stewardship program on antibiotic resistance and length of hospital stay of patients at Bicol Regional Training and Teaching Hospital. Specifically: (1) Determinedhe top three isolated organisms in the hospital antibiogram of 2017. (2) Determined the patient’s average length of hospital stay and antibiotic resistance of top three isolated organisms before AMS (2017), (3) Monitored the top three isolated organisms of 2017 after one (1) year of AMS (2019) in terms of Average length of hospital stay and Antibiotic Resistance, and (4) Compared the patient’s average length of hospital stay and antibiotic resistance of top three isolated organisms before AMS (2017) and after AMS (2019). The study used a retrospective and descriptive study, this design aimed to compare the antibiotic resistance and length of hospital stay of patients during the pre AMS (January 1 – December 31, 2018) and post AMS era (January 1 – December 31, 2019). Patient with respiratory infections shown at greater risk to be infected with Klebsiella pneumoniae and pseudomonas sp, while patient with would injury or related condition are at greater risk for staphylococcus infection. The pediatric patients are at higher risk for prolonged hospital stay compare to all other patients from the medical, surgical and OB- Gyne ward during the Pre AMS. After the 1st year of AMS (2019) implementation reveals a significant percentage of patients who still develop antibiotic resistance to Penicillin, followed by ceftriaxone and Amoxicillin. It implies that the impact of AMS to the average LOHS in 1- year period of its implementation was not significant, maybe due to other underlying factors not considered in this study, however the reduction in the antibiotic resistance can be attributed with the proper use of antibiotics with the regulation of Antimicrobial Stewardship program of BRTTH.