INTRODUCTION: Indiscriminate prescribing and using of antibiotics have led to the development of antimicrobial resistance (AMR). To reduce this problem, the World Health Organization (WHO) developed the “Access”, “Watch”, and “Reserve” (AWaRe) classification of antibiotics that promotes antimicrobial stewardship (AMS). In Zambia, there are gaps in practice regarding prescribing of antibiotics based on the AWaRe protocol. This study assessed antibiotic prescribing patterns in adult in-patients in selected primary healthcare hospitals in Lusaka, Zambia. MATERIALS AND METHODS: This retrospective cross-sectional study was conducted using 388 patient medical files from September 2021 to November 2021, five primary healthcare hospitals namely; Chawama, Matero, Chilenje, Kanyama, and Chipata. Data analysis was performed using the Statistical Package for Social Sciences version 23. RESULTS: Of the selected medical files, 52.3% (n = 203) were for male patients. Overall, the prevalence of antibiotic use was 82.5% (n = 320) which was higher than the WHO recommendation of a less than 30% threshold. The most prescribed antibiotic was ceftriaxone (20.3%), a Watch group antibiotic, followed by metronidazole (17.8%) and sulfamethoxazole/trimethoprim (16.3%), both belonging to the Access group. Furthermore, of the total antibiotics prescribed, 41.9% were prescribed without adhering to the standard treatment guidelines. CONCLUSION: This study found a high prescription of antibiotics (82.5%) that can be linked to non-adherence to the standard treatment guidelines in primary healthcare hospitals. The most prescribed antibiotic was ceftriaxone which belongs to the Watch group, raising a lot of concerns. There is a need for rational prescribing of antibiotics and implementation of AMS programs in healthcare facilities in Zambia, and this may promote surveillance of irrational prescribing and help reduce AMR in the future.