Objectives: To describe the usefulness of electronic medical records (EMRs) and a computerized physician order entry (CPOE) system to support and assess an antimicrobial stewardship programme (ASP). Methods: At the study hospital, infectious diseases specialists supervise antimicrobial prescription when solicited by physicians in charge of patients. From January to October 2015, treatment days of antibiotic prescription, supervised or unsupervised by infectious disease specialists (SAP or UAP, respectively) in all wards, except intensive care units emergency department, bone marrow transplantation units, and paediatric units, were calculated. Embedding recommendations on carbapenem indications as a checklist into the CPOE system, a self-administered ASP was implemented in 2017. EMRs were reviewed to determine global compliance with carbapenem prescription guidelines (combining introduction of therapy and 72-h assessment) before and after implementation of a self-administered ASP in departments with a low SAP rate for these antibiotics. Results: Among 16 090 prescriptions extracted, 19.9% were SAPs. Three patterns of prescription were identified. The first pattern (amoxicillin-clavulanate, ceftriaxone) was characterized by a high UAP rate in every department, the second pattern (cloxacillin, rifampin) was characterized by a high SAP rate in every department, and the third pattern (broad-spectrum beta-lactams) was characterized by heterogeneous distribution of SAP/UAP among departments. Carbapenem prescription was reviewed in five departments with a low SAP rate for carbapenems over 6 months: 94 before and 107 after implementation of the self-administered ASP. Global compliance with guidelines increased significantly from 22% to 37% (risk difference 15%, 95% confidence interval 2.3–28.5%; P=0.02). Conclusion: A clinical information system may help to rationalize antibiotic stewardship in a context of scarce medical resources. Mapping of antibiotic prescriptions and self-supervision are efficient, complementary and easy-to-implement tools.