Using a survey conducted with 274 Canadian companies, this study aimed to validate Ulrich’s four-role typology (1997) characterizing the various roles of human resources departments (HRD) as well as measure the effect of these HRD roles on organizational performance. An exploratory factor analysis reproduced Ulrich’s four HRD roles (1997) and revealed a fifth administrative role, which relates to the control of administrative procedures specific to human resources management (HRM). This fifth role is distinct from Ulrich’s “administrative expert” role (1997), associated with the development and implementation of human resources (HR) policies. The empirical data further demonstrated that HRDs’ adoption of all of these roles, and in particular a mastery of strategic roles, is positively correlated with organizational performance indicators. HRDs that place an emphasis on administrative or operational roles have little impact on organizational performance.