Depression and anxiety disorders are thought to be common in palliative cancer care, but there is inconsistent evidence regarding their relevance for other aspects of quality of life. In the Canadian National Palliative Care Survey, semi-structured interviews assessing depression and anxiety disorders were administered to 381 patients who were receiving palliative care for cancer. There were 212 women and 169 men, with a median survival of 63 days. We found that 93 participants (24.4%, 95% confidence interval=20.2-29.0) fulfilled Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnostic criteria for at least one anxiety or depressive disorder (20.7% prevalence of depressive disorders, 13.9% prevalence of anxiety disorders). The most frequent individual diagnosis was major depression (13.1%, 95% confidence interval=9.9-16.9). Comorbidity was common, with 10.2% of participants meeting criteria for more than one disorder. Those diagnosed with a disorder were significantly younger than other participants (P=0.002). They also had lower performance status (P=0.017), smaller social networks (P=0.008), and less participation in organized religious services (P=0.007). In addition, they reported more severe distress on 14 of 18 physical symptoms, social concerns, and existential issues. Of those with a disorder, 39.8% were being treated with antidepressant medication, and 66.7% had been prescribed a benzodiazepine. In conclusion, it appears that depression and anxiety disorders are indeed common among patients receiving palliative care. These disorders contribute to a greatly diminished quality of life among people who are dying of cancer.