The use of health information technology (IT) is increasing around the world. However, as complex IT systems are implemented, new types of errors are introduced. These can disrupt workflow and care delivery, and even lead to patient harm. The purpose of this paper is to examine the patterns and causes of IT system downtime in a hospital setting. We examined all the downtime events that were recorded by a hospital IT department from February 2010 to October 2012. On average downtime disrupted care delivery for 49 hours per year with 51% of total downtime between 9 am and 5 pm. These results show that there is a need for safer design and implementation of IT systems. Further studies are required to measure the effects of downtime on care delivery and patient outcomes in digital hospitals.