Clinical trial protocol documents play an important role in clinical research. However, clinical protocol writing remains a complex and relatively un-studied process. Protocols are often written by teams of people, yet little prior research has captured the problems or analyzed the collaboration support needs of protocol writers. Here we present the results of an initial ethnographic study into the clinical trial protocol writing processes at a representative cooperative clinical trial group funded by National Cancer Institute (NCI). We analyzed the collaborative nature of the writing process, identified common problems, derived information and communication support needs of collaborative clinical protocol writers, and provided recommendations to streamline the process. We believe that this paper contributes useful implications for the design of future collaborative clinical protocol writing tools.