This paper reports on findings from an examination of a nursing information system through the lens of Activity Theory. The information system was designed to support real-time nursing documentation in acute care hospital contexts. The objective was to enable superior nursing care to ensue by providing nurses with the opportunity to document patient care data into a tablet computer located at the patient bedside. The system was evaluated in a not-for-profit acute care hospital’s wards during its implementation. Nurses’ interactions with the system and their perceptions were collected and analysed through the lens of Activity Theory. The analysis highlighted nurses’ positive attitude towards the system and identified potential mediation capabilities as well as areas for improvements. Activity Theory was found to be useful to examine the positive and potentially problematic aspects of this new nursing information system.