Does working from home on a given day complicate or rather facilitate combining work and home roles that day, why and for whom? To answer these questions, we examined how a teleworking day affects daily work-to-home conflict and daily home-to-work conflict. Based on boundary theory, we expected these relationships to be mediated by daily role transitions and moderated by employees’ preferences to protect their home(/work) domain from work(/home) interruptions. Hypotheses were tested through multilevel moderated mediation modeling using diary data collected during 14 consecutive workdays with 81 employees (N = 678 data points). In line with our expectations, employees were found to make more work-to-home transitions (i.e. interruptions of work activities to deal with home demands during work hours) on teleworking days, which was related to lower work-to-home conflict but higher home-to-work conflict on these days. They also made more home-to-work transitions (i.e. interruptions of home activities to deal with work demands after hours) on teleworking days, which was related to more work-to-home conflict on these days. The latter effect was stronger for employees with a home protection preference. There was no moderating impact of work protection preference. Overall, employees experienced less work-to-home conflict but more home-to-work conflict on teleworking days compared to non-teleworking days.