Understanding knowledge work and supporting it with information systems (ISs) are challenging tasks. Although there have been numerous studies on knowledge work in varying contexts, many of them are not detailed enough or outdated, particularly with respect to IS support. Knowledge work underwent dramatic changes over recent years, and empirical research studies into how knowledge work is currently performed are scarce. Ethnography would appear to be the most suitable qualitative research method for studying knowledge work, were it not too time-consuming, costly and unfocused for the fast-changing IS domain. Moreover, if we want to ensure the take-up of results from qualitative studies, these need to be transformed into artefacts for the design and engineering of IS requirements. This paper proposes a procedure for the study of knowledge work practices that was adapted from collaborative ethnography, and can be used to inform requirements gathering for, and the design of, IS. The procedure is illustrated with an example of a collaborative ethnographic study which involved seven organisations in four European countries who took part in a large-scale international IS research and development project. The paper also critically discusses the procedure's implementation and its limitations.