Information and communication technologies (ICT) are more prevalent in the work environment than ever before, creating benefits for employees (e.g., automation of tedious tasks) and organizations (e.g., cost savings). However, evidence indicates that individual interaction with ICT may lead to detrimental effects such as symptoms of lowered psychological and physiological health (e.g., fatigue), reduced job satisfaction, and lowered productivity. This negative side of ICT is referred to as technostress (TS). Although the term was coined more than 30 years ago, the phenomenon has received increased research attention in recent years, and this, in turn, has facilitated the development of new insights into the phenomenon. Often, however, research results have been derived based on mere survey studies or in laboratory settings. Thus, it is the purpose of this study to draw a more complete picture of the factors and mechanisms that lead to TS by studying the phenomenon in the field (i.e., in an organization), answering the main research question: How and why does TS occur in organizations, and how do employees cope with it? Based on existing cybernetic theories of organizational stress, we developed a new integrated theoretical framework to study TS in organizations, which constitutes the basis for a field study. As the phenomenon is highly dynamic in nature (e.g., due to spontaneous events like computer break downs), a longitudinal approach (i.e., repeated data collection over several months at a time) is needed to study TS causes and effects. Also, using traditional means of data collection which involve the perceptions of individuals alone (e.g., interviews, focus groups, or questionnaires) are not be sufficient to draw a complete picture of this phenomenon. It has been shown that the often unconscious detrimental effects of TS (e.g., strains that result from elevations of stress hormones) cannot be fully reported by participants. This, in turn, makes data collection methods from neurobiology and medicine an important complement to the more traditional methods. In addition to interviews and questionnaires, among other more traditional methods, we therefore also measure bodily symptoms, including heart rate, blood pressure, and stress-related substances such as cortisol and alpha-amylase. Based on the findings, we advance our theoretical framework, thereby contributing to a better theoretical understanding of TS. Also, we provide a methodological contribution by showing how a mixed methods approach can be applied to the study of TS. The results of this study facilitate the development of effective TS countermeasures.