It is recognised that medicines errors are common in institutional healthcare settings such as hospitals and residential care homes. Electronic prescribing (EP) systems, also known as computerised physician order entry (CPOE) systems, have the potential to reduce medicines errors in hospitals and also to provide other organisational benefits such as improving clinical workflows and hospital discharge process efficiency. This chapter reviews the development, use and benefits of electronic prescribing systems in hospitals. Electronic prescribing systems have a clear-cut impact on prescribing errors and possibly medicines administration errors, and they have been shown to improve quality of care. However, the evidence for their financial benefits is not robust at present, and there is little evidence for their impact on patient outcomes. Moreover, EP systems are sociotechnical systems, and their safety and benefits are leveraged by appropriate optimisation of the system in the health provider organisation. The chapter also provides a discussion of EP implementation and training issues, and outlines the use of electronic medicines administration records (EMARs) in residential care homes.