Purpose As more people survive cancer, it is necessary to understand the long-term impact of cancer. We investigated whether cancer survivors are at increased risk for hospitalization for depression. Methods We linked data on all 5,703,754 persons living in Denmark on January 1, 1973, or born thereafter to the Danish Cancer Registry and identified 608,591 adults with a diagnosis of cancer. Follow-up for hospitalization for depression in the Danish Psychiatric Central Register from 1973 through 2003 yielded 121,227,396 person-years and 121,304 hospitalizations for depression. The relative risk (RR) for depression among cancer survivors relative to the cancer-free population was estimated by Poisson regression analysis with adjustment for age and period and stratified by sex, site of cancer, and extent of disease. Results The risk for depression in the first year after a cancer diagnosis was increased, with RRs ranging from 1.16 (95% CI, 0.90 to 1.51) in women with colorectal cancer to 3.08 (95% CI, 1.88 to 5.02) in men with brain cancer. Decreasing but still significant excess risks during subsequent years were observed for most specific cancers. The risk remained increased throughout the study period for both men and women surviving hormone-related cancers, for women surviving smoking-related cancers, and for men surviving virus- and immune-related cancers. Conclusion This study confirms an increased risk for depression in patients facing a disruptive event like cancer. Early recognition and effective treatment are needed to prevent admission of cancer survivors for depression.