This paper presents an ethnographic study investigating how nurses assemble information to start their shift’s work. We examined this process before and after the adoption of a Computerized Prescriber Order Entry (CPOE) system in an inpatient unit of a large teaching hospital. Before the CPOE adoption, nurses used several collaboratively-created group working documents to assist in this information assembling process; after the CPOE adoption, they mainly used the CPOE itself for their information needs. We found while computerization facilitated medical data assembling process and improved order handling practice, it also resulted in some information gaps in understanding patients in their larger care context. We analyzed what it means when the computerization of medical information turns local knowledge into more readily available and public information objects, as well as what that means for patients and patient care.