This paper examines the potential of demographic, personal, material and behavioural characteristics, other psychosocial features of the work environment and job satisfaction to explain associations between self-reported job insecurity and health in a longitudinal study of British white-collar civil servants. Strong associations were found between self-reported job insecurity and both poor self-rated health and minor psychiatric morbidity. After adjustment for age, employment grade and health during a prior phase of secure employment, pessimism, heightened vigilance, primary deprivation, financial security, social support and job satisfaction explained 68% of the association between job insecurity and self-rated health in women, and 36% in men. With the addition of job control, these factors explained 60% of the association between job insecurity and minor psychiatric morbidity, and just over 80% of the association with depression in both sexes.