Medication monitoring of ambulatory rheumatology patients on Disease Modifying Anti-Rheumatic Drugs (DMARDS) is time consuming and complex, with possibilities for error. Electronic systems have the potential to improve the process. The aim of this study was to evaluate the impact of an electronic Drug Monitoring System (eDMS) on the time nurses' spent on clinical documentation associated with monitoring. The study was conducted with all nurses (n=4) in the Rheumatology Department of a large metropolitan Australian teaching hospital. The eDMS was designed as a module of the Hospital Clinical Information System (HCIS) to assist clinicians in monitoring rheumatology patients on DMARDS. Timing data were collected using a modified time and motion work measurement technique using software on a handheld computer. Data included the time nurses spent on documentation regarding medication monitoring before and after the implementation of the eDMS. Results showed that following implementation of the eDMS nurses spent significantly less time documenting medication monitoring information (13.6% to 7.2%, P<.0001). The cumbersome paper-based Drug Monitoring Patient List was replaced entirely by the eDMS. Consequently, there was a significant decrease in the time nurses spent using the HCIS (13.01% to 2.8%, p < .0001) for monitoring and the use of loose-leaf paper also decreased (7.6% to 5.0%, p = 0.002). The eDMS made the process of drug monitoring quicker and simpler for nurses and thus permitted them to increase their time spent in direct patient care.