The authors developed and tested a process model of adaptation to shiftwork, which hypothesizes that various individual and situational variables influence the development of sleep and social and domestic disturbances. Both types of disturbances trigger various types of coping behavior, leading to several proximal outcomes. The end result is the development of chronic health problems in the form of digestive and cardiovascular symptoms. The model was tested with survey data collected from 2 samples of nurses (N = 1,532) in the United Kingdom and was cross-validated against a 3rd sample of industrial workers (N = 370). Results indicate support for the model across the 3 samples, although some sample-specific and subgroup effects were found. Results have direct implications for the development of shiftwork theory and interventions.