Introduction: Thromboembolism is common in lung cancer. Current thromboprophylaxis guidelines lack specific recommendations for appropriate strategies in this high thrombotic risk patient cohort. We profiled lung cancer patients receiving anti-cancer therapy. Thromboembolism incidence and thromboembolism-related mortality rates are reported and we explored patient, disease, and treatment-related risk factors associated with higher thrombotic rates. Methods: Retrospective review of lung cancer patients referred to a Comprehensive Cancer Centre between 01/07/2011 and 30/06/2012 for anti-cancer therapy. Data were collected from medical, pharmacy, pathology and diagnostic imaging electronic records. Results: After a median follow up of 10 months (range: 0.03-32 months), 24/222 patients (10.8 ) had developed radiologically confirmed thromboembolism; 131 events per 1000 person-years (95 CI 87-195). Thromboembolism occurred equally in patients with non-small cell and small cell lung cancer (10.8 and 10.5 respectively), and more frequently among patients with adenocarcinoma compared to squamous cell carcinoma (14.7 and 5.3 respectively). Chemotherapy-treated patients experienced thromboembolism more often than patients who did not receive chemotherapy (HR 5.7 95 CI 2.2-14.8). Radiotherapy was also associated with more frequent thromboembolism (HR 5.2 95 CI 2.0-13.2). New lung cancer diagnosis, presence of metastatic disease, second primary malignancy and Charlson Index =5 were also associated with higher rates of thromboembolism. Importantly, pharmacological thromboprophylaxis (P-TP) was not routinely or systematically prescribed for ambulant lung cancer patients during any treatment phase, at this institution. The majority (83 ) of thromboembolic events occurred in the ambulatory care setting. Conclusion: Morbidity and mortality from thromboembolism occurs frequently in lung cancer. Thromboprophylaxis guidelines should be developed for the ambulatory care setting.