Background: Venous thromboembolism (VTE) is a common complication in cancer patients, but contemporary data on the incidence and characteristics of cancer-associated VTE in different racial populations is limited. We sought to measure the incidence rate and characteristics of cancer-associated VTE in a racially diverse population. Methods: We performed a prospective, population–based cohort study of VTE in Oklahoma County, OK during April 1, 2012–March 31, 2014. Surveillance staff regularly visited all tertiary care and relevant outpatient facilities in the county and reviewed the text from all imaging results of chest computed tomography or magnetic resonance imaging, lung perfusion scans, and ultrasound of the extremities to identify cases of VTE. Data on patient characteristics were collected from the electronic medical record. VTE was considered cancer-associated if the patient had a history of cancer other than basal or squamous cell skin cancer. Cancer was defined as “active” if metastatic or diagnosed within 6 months prior to VTE. Associations and incidence were calculated using the chi-square test and Poisson regression, respectively. Results: Of 3,255 patients with ≥1 VTE event (deep-vein thrombosis and/or pulmonary embolism), 732 (23%) had a history of cancer, of whom 309 had active cancer. The types of cancer varied widely. The age-adjusted incidence of cancer-associated VTE was 648 per 100,000 adult population (age ≥ 18). Incidence increased with each decade of age. The racial/ethnic-specific incidence rates were as follows (each per 100,000): Whites non-hispanic (607), Blacks non-Hispanic (557), Native Americans (128), Asian/Pacific Islanders (113) and Hispanics (70). Risk factors for VTE among the 732 with cancer-associated VTE included previous VTE (19%), hospitalization (37%), surgery (33%), and central venous catheter (22%). Of those with a history of cancer ≥ 6 months previously, 32% had no other identifiable VTE risk factor. Conclusions: Cancer-associated VTE comprised about 20-25% of the total population burden of VTE. The incidence varied substantially by race/ethnicity. An appreciable proportion of those with a history of cancer ≥ 6 months previously subsequently developed VTE in the absence of other risk factors.