This thesis is about workplace stress due to email and computer-mediated communication use. Rather than focusing on email-specific constructs such as email overload, email interruptions or email use outside working hours, it draws an overarching construct of ‘email stress’ based on previous theories of traditional workplace stress. This cross-disciplinary approach emphasizes the individually appraised nature of email stress. As a result, the thesis gives a central importance to individuals using email and, more importantly, to their desired email use. The thesis is based on a three-stage multi-method design involving quantitative surveys and qualitative interviews. The results of these studies are part of the four self-sufficient papers composing the thesis. While the papers make their own contributions, they also build on one another to advance the understanding of email stress as being a kind of stress that is individually appraised and that affects workplace well-being. The papers adapt theories of workplace stress, such as Person-Environment Fit and Cybernetics, to the study of email stress, and empirically validate these adaptations. They reveal how email stress can be the result of unfulfilled desires in terms of email use or a reason for desiring fewer emails. As employees do not often have control over their email use, the findings encourage the emergence of a more empathetic organizational culture taking into account individuals’ desires in terms of email use.