||BACKGROUND: Few studies have evaluated cancer risk following venous thromboembolism (VTE). Both VTE and cancer disproportionately affect older adults. METHODS: Using linked Surveillance, Epidemiology, and End Results (SEER)-Medicare data, we evaluated 1.2 million cancer cases and 200,000 controls (66-99 years old, 1992-2005). VTEs occurring before selection were identified using Medicare claims. Logistic regression was used to estimate ORs. RESULTS: VTE was present in 2.5% of cases and 2.2% of controls. VTE was associated with risk of cancers of the lung [OR = 1.18; 95% confidence interval (CI), 1.12-1.23], stomach (OR = 1.19; 95% CI, 1.09-1.30), small intestine (OR = 1.42; 95% CI, 1.17-1.71), colon (OR = 1.25; 95% CI, 1.18-1.31), gallbladder (OR = 1.39; 95% CI, 1.16-1.67), pancreas (OR = 1.53; 95% CI, 1.43-1.64), soft tissue (OR = 1.43; 95% CI, 1.21-1.68), ovary (OR = 1.35; 95% CI, 1.22-1.50), and kidney/renal pelvis (OR = 1.34; 95% CI, 1.23-1.46), and melanoma (OR = 1.17; 95% CI, 1.08-1.27), non-Hodgkin lymphoma (OR = 1.27; 95% CI, 1.20- 1.35), myeloma (OR = 1.48; 95% CI, 1.35-1.63), and acute myeloid leukemia (OR = 1.35; 95% CI, 1.19-1.54). Strongest risks were observed within 1 year of VTE diagnosis, but risks were elevated more than 6 years after VTE for colon cancer (OR = 1.24; 95% CI, 1.12-1.37), pancreatic cancer (OR = 1.33; 95% CI, 1.15-1.54), and myeloma (OR = 1.35; 95% CI, 1.10-1.66). Few differences in risk were observed by VTE subtype. Cancers of the lung, stomach, and pancreas were more likely to have distant metastases within one year after VTE. CONCLUSION: Among elderly adults, cancer risk is elevated following VTE diagnosis. IMPACT: Short-term associations with cancer are likely driven by enhanced screening following VTE and reverse causation. While obesity, other comorbidities, and smoking cannot be excluded as explanations, longer-term elevations for select cancers suggest that some VTEs may be caused by cancer precursors.