Organizations in most industrialized countries have engaged in various adaptive strategies in order to remain competitive in a gradually more unpredictable environment. Restructurings, privatizations, mergers and acquisitions have become more frequent, and typically involve personnel reductions through layoffs, offers of early retirement, and increased utilization of subcontracted workers. Although these reorganizations differ in many ways, they usually have at least one thing in common – they lead to the workforce being permeated with worries regarding the future. Job insecurity can be defined as a perceptual phenomenon, reflecting the fear of involuntary job loss. In the literature, job insecurity is often considered a classical work stressor, and it has been linked to several negative outcomes. A growing number of studies have documented that job insecurity is related to job dissatisfaction, impaired organizational commitment, increased turnover intention, and physical as well as mental health complaints. There are also indications that the worry of job loss may be related to factors such as impaired compliance with safety procedures, ischemic heart disease occurrence, and absenteeism. However, whereas previous research has concluded that job insecurity has psychological, behavioral as well as health-related consequences, there is insufficient evidence to draw any causal inferences. The aim of the present study is to shed light on the issue of causality in the relationship between job insecurity and a potential outcome that has attracted comparatively limited research attention – absenteeism. Drawing upon the literature on work stress, it is reasonable to suggest that job insecurity may lead to increased absenteeism from work. Equally plausible, however, would be to assume that individuals with high absenteeism records would feel more at risk in organizations where there is a threat of layoffs. The study also aims at ruling out the yet alternative hypothesis that both job insecurity and absenteeism are caused by third variables, by controlling for factors such as seniority and well-being. Longitudinal data for this study are currently being collected using mail questionnaires among white-collar workers in a Swedish organization. The second wave of data collection, conducted a year after Time 1, is currently being completed. Preliminary analyses based on cross-sectional Time data indicate a positive association between job insecurity and absenteeism. The longitudinal design will make it possible to test various alternative models of causality. Latent variable cross-lagged analysis will contribute to the understanding of the development and consequences of job insecurity by shedding light on the issue of absenteeism in this process.