Background: Sick children frequently have antibiotics prescribed as part of their treatment. Inappropriate use of antibiotics, especially broad-spectrum antibiotics, can result in the development of antibiotic resistance and the consequences of antibiotic resistance. In this study, we use routinely collected data to describe the patterns and identify factors influencing antibiotic prescription among admitted children. Methods: Routine data collected from medical records of children aged 2 months or older admitted between 2014 and 2020 to paediatric wards of 12 hospitals which are part of a Clinical Information Network (CIN) are used. Multivariable mixed effects logistic regression is used to assess determinants of antibiotic prescription with a random slope and intercept for hospital level. Results: A total of 127,984 antibiotic prescriptions were made in 107,500 participants included in the study where 81.1% (87,183/107,500) had one or more antibiotic prescriptions. The commonly prescribed antibiotics were a combination of benzylpenicillin and gentamicin (37,939/127,984 - 29.6%), ceftriaxone (31,172/127,984 - 24.6%) and oral amoxicillin (12,593 /127,984 - 9.8%). Factors associated with antibiotic prescription were history of cough (adjusted odds ratio (aOR), = 2.06, 95% confidence interval (CI):1.966 - 2.152), bloody diarrhoea (aOR=5.6, CI:4.453 - 7.036), diagnoses of pneumonia (aOR=27.66, CI:21.768 - 35.154), malnutrition (aOR=6.3, CI:4.558 - 8.701) and meningitis (aOR=11.85, CI:9.502 - 14.779). Antibiotic prescription was less likely in children diagnosed only with severe anaemia (aOR=0.8, CI:0.742 - 0.870), malaria (aOR:0.22, CI:0.201 - 0.231), diarrhoea (aOR:0.36, CI:0.331 - 0.398), and dehydration (aOR=0.4, CI:0.347 - 0.464). Conclusion: Antibiotics are prescribed in approximately four of every five children admitted to paediatric wards of Kenyan hospitals. Prescriptions are mainly in patients who fulfil syndromic clinical criteria where antibiotics are indicated. Without the introduction of reliable pathogen diagnostics, it will be difficult to reduce antibiotic prescriptions among admitted children.