Chronic pain and depression are two of the most common health problems that health professionals encounter, yet only a handful of epidemiological studies have investigated the relationship between these conditions in the general population. In the present study we examined the prevalence and correlates of major depression in persons with chronic back pain using data from the first cycle of Canadian Community Health Survey in a sample of 118,533 household residents. The prevalence of chronic back pain was estimated at 9% of persons 12 years and older. Rates of major depression, determined by the short-form of the Composite International Diagnostic Interview, were estimated at 5.9% for pain-free individuals and 19.8% for persons with chronic back pain. The rate of major depression increased in a linear fashion with greater pain severity. In logistic regression models, back pain emerged as the strongest predictor of major depression after adjusting for possible confounding factors such as demographics and medical co-morbidity. The combination of chronic back pain and major depression was associated with greater disability than either condition alone, although pain severity was found to be the strongest overall predictor of disability.