Does the presence of a unionized nursing workforce retard U.S. hospitals’ transition from paper-based to electronic health records (EHRs)? After tying archival data on hospitals’ structural features and health information technology (IT) investment patterns to self-gathered data on unionism, I find that hospitals that bargain collectively with their registered nurses (RNs) appear to delay or forego the transition away from paper, consistent with existing theory and research in industrial relations and institutional economics. However, this relationship is fully mediated by a hospital’s payer mix: those serving a larger share of less lucrative, elderly, disabled, and indigent patients are more likely to adopt EHRs if they are unionized than if they are not, a result that holds even at the median payer mix. Indeed, this accords with research on the interplay of labour and technology as the aforementioned dynamics are driven entirely by RN-exclusive bargaining units for whom the new IT serves as a complement rather than as a substitute in production. Given the outsized role that unions play in the U.S. healthcare sector, the overall sluggish performance of the sector, and the expectations that policymakers have for EHRs, evidence that these unions are welfare-enhancing should be welcome news.