Electronic Human Resource Management (e-HRM) is often assumed to increase HRM service quality. This paper empirically examines the relationship between e-HRM and HRM service quality and addresses two calls from recent e-HRM studies, namely to highlight (i) the importance of the interplay between technological and organizational aspects and (ii) the finding that improved HRM service quality is a consequence of e-HRM implementation. We argue that the key drivers of HRM service quality are the strengths both of HRM and of e-HRM. The relationship may be mediated by the frequency of e-HRM usage. In addition, building on Adaptive Structuration Theory, the degree to which mediation occurs may differ within regimes of high and low e-HRM appropriation. We use moderated mediation analysis on a sample of 140 employees of an administration unit to shed light on the drivers of HRM service quality. While we identify strong positive direct effects of HRM strength and of e-HRM strength, we fail to uncover either mediation or contingent mediation effects. The study contributes to e-HRM research by identifying the main antecedent of HRM service quality as HRM strength.