Background Antibiotics use in in children are different from adults due to a lack of data on pharmacokinetics, pharmacodynamics, efficacy and safety of drugs, different physiological spectrum, pediatrics populations being vulnerable to the majority of the illnesses, and the adverse effect of their irrational use is more serious. However, antibiotic use is not explored much in a paediatric population. The current study focused on antibiotic use among pediatric population using data from a tertiary hospital in Ethiopia. Methods A retrospective cross-sectional study collated data from 614 pediatrics patients admitted in pediatrics ward at Jimma University Teaching Hospital, Southwest Ethiopia. Descriptive analyses were performed to describe the type and pattern of antibiotics. The number of prescriptions per a patient was also compared with the WHO standard. Data analysis was carried out using SPSS version 20 for mackintosh. Results Antimicrobials were prescribed for 407(86.4%) patients of which 85.9% were in the form of injectables. A total of 1241 (90%) medicines were administered parenterally followed by oral 110 (8%). The maximum number of medicines per prescription was eight for all types of drugs in general, and five for antimicrobials in particular. All antimicrobials were prescribed empirically without any microbiological evidence. Pneumonia, sepsis and meningitis were the main reasons for antimicrobial use in the ward. Out of the total of 812 antibiotics prescribed; Penicillin G crystalline was the most (20%) frequently prescribed, followed by gentamicin (19%) and ampicillin (16). Conclusions Majority of the prescribed antibiotics were antimicrobials, and was in the form of injectables. Antimicrobials were over prescribed and the number of drugs per prescription was also far from WHO recommendation. Strict prescribing standard guidelines and treatment habits should be developed in the country, to prevent antimicrobial resistance.