Purpose - This research analyzes and tests the impact of some resource-based determinants on sourcing decisions in an IS domain. Design/methodology/approach - By applying the insights provided by the resource-based view of the firm, some hypotheses to explain sourcing decisions regarding the implementation of an information system was developed. These hypotheses are tested in a specific functional area - human resources - using binomial logistic models. Primary data was collected through a survey of large Spanish firms. Findings - Results confirm that HRIS implementation capabilities, and not the mere set of technical skills, play a major role in sourcing decisions. However, only when a specific level of both experience in that function and relationship between client and provider teams is reached will these capabilities allow the firm to outperform competitors and become a key determinant of the governance mode. Support for the influence of the strategic contribution of the HRIS was also found. Originality/value - Unlike prior research, which stopped with the theoretical application of a resource-based perspective to explain IS sourcing decisions, the author takes things a step further and operationalizes its insights. By using the IS function as the unit of analysis, a theoretically derived multidimensional measure of IS implementation capability was developed. Moreover, timing issues was considered when measuring this concept.