Background: The Demand Control Model (DCM) and the Effort-Reward Imbalance Model (ERI) offer putative explanations of the relationship between stressful working conditions, job strain, and psychological and physical ill health. Aims: The aims of this study are to: (a) compare the predictive powers of the two models for explaining perceived job stress and mental distress amongst workers as a whole, (b) identify whether a model which combines dimensions of the DCM and ERI might have more predictive power than either of them separately, and (c) ascertain whether the models make distinct contributions to explaining stress at work in specific occupational settings. Methods: Statistical analysis was carried out on data collected from a cross-sectional postal survey of a random sample (n=7,069), of the adult population in an urban area in Southern England. The analysis focused on the 4,135 respondents who were in paid employment. Results: There was little support for combining the models as the combined model was dominated by the predictive power of dimensions from the ERI. However, the results also showed that the models or dimensions of the models made distinct contributions to explaining perceived work stress in different types of occupation. Conclusions: There is little evidence to support a combined model of work characteristics. The ERI appears to be the stronger of the two models although the DCM has explanatory value for specific occupations.