Adverse events in hospitals, events in which harm results to a person receiving health care, are well documented (Wilson 1995, Hepler 2001). However, while factors such as lack of training and other human factors (Wilson et al, 1995) have been identified as contributing to this problem, there is a paucity of research attempting to link information systems failure to adverse patient events. This paper examines the co-occurrence of these issues. Specifically, we look at two case studies relating to treatment decisions in two large public hospitals. We examine the incidence of adverse events in hospitals with regard to errors in treatment decisions where information delivery is unreliable. We ask the question: can information delivery problems lead to adverse events for patients? It is important to empirically test the impact of this particular factor in the complex environment of hospitals where a full range of factors may adversely affect patient care. We have reason to believe that poor information systems can have a negative impact on patient care leading to adverse events where data delivery and availability problems exist and are not being addressed by hospital management. Further findings of this paper are that I.S. improvements need to be complimented by cultural changes in hospitals that support the use of computerised systems, and enhanced approaches to I.S. governance in the context of healthcare.