To investigate the impact of the introduction of an electronic medication management system on the proportion of patients with a recorded medication reconciliation on admission, the time from admission to when medication reconciliation was performed, and the characteristics of patients receiving this intervention pre-and post-implementation. An electronic medication management system was implemented in an Australian hospital from May to July 2015. A retrospective observational study was conducted in three wards across two phases; pre- (August 2014) and post- (August 2015) implementation. The study sample included every second patient admitted to these wards. A total of 370 patients were included, 179 pre- and 191 post-implementation. The proportion of recorded admission medication reconciliation significantly increased post-implementation in all study wards; coronary care unit (40 vs 68%, p=0.004), gastroenterology ward (39 vs 59%, p=0.015), and the neurology ward (19 vs 45%, p=0.002). The proportion of patients with recorded medication reconciliation within 24h of weekday admissions, or 48-72h of weekend admissions, increased from 47% pre- to 84% post-implementation. Admission medication reconciliation was recorded within a median of 1.0day for weekday admissions pre- and post-implementation (IQR 1.1 vs 0.2, respectively), and 3.5days (IQR 2.0) pre-implementation vs 1.5days (IQR 2.0) post-implementation for weekend admissions. Overall, across both phases pre-and post-implementation, admission medication reconciliation was recorded for patients who were significantly older (median 77 and 71 years, p<0.001), had a higher number of preadmission medications (median 6.5 and 5.0 medicines, p=0.001), and had a longer hospital stay (median 6.5 and 5.1days, p=0.003). A significantly higher proportion of patients with recorded medication reconciliation in the pre-implementation phase experienced polypharmacy (61%, p=0.002), hyperpolypharmacy (15%, p=0.001), and used a high-risk medication (44%, p=0.007). Implementing an electronic medication management system facilitates the medication reconciliation process leading to more high risk patients receiving this service on admission to hospital and in a more timely manner. The impact of electronic medication reconciliation on patient safety and clinical outcomes remains unknown.