The aim of this study was to investigate the cross-sectional and longitudinal effect of job insecurity on common infections and health complaints. Selfadministered questionnaire data from the Maastricht Cohort Study (n 12,140) were used. We used Generalized Estimating Equations analyses to calculate pooled odds ratios (ORs) and 95% confidence intervals. A cross-sectional relationship between job insecurity and common infections or health complaints was found. For the longitudinal relationship, the largest effect was found for flu-like illness (OR 1.39; CI 1.22–1.57) and health complaints (OR 1.51; CI 1.39–1.64). We additionally corrected for health behavior, the presence of a long-standing illness, and work-related demands, resulting in lower ORs. An increase in common infections or health complaints has a substantial impact on employee well-being and may result in economic consequences for the company.(J Occup Environ Med. 2003; 45: 123–129)