Background: Previous studies suggest that spouses of cancer patients are at increased risk for several chronic diseases. We investigated mortality in relation to cancer morbidity in the stable female partner. Methods: We established a national retrospective cohort study of 1,422,131 men who had lived continuously with the same partner for at least 5 years and used Cox regression analysis to assess the association between experiencing cancer in a cohabiting partner and all-cause mortality. Results: The risk for death was only slightly elevated among men whose partner had cancer than for men whose partner remained free of cancer (hazard ratio = 1.03; 95% confidence interval = 1.01-1.05). Conclusions: Although a cancer diagnosis in a spouse might be associated with considerable distress, our study indicates that the risk for death differs only slightly between men living with a partner with cancer and those living with a partner without cancer.