OBJECTIVE: To quantify and describe current cancer clinical trial activity in Australia and help guide future trials research using trial registries. DESIGN AND SETTING: Data from cancer trials recruiting in Australia at 31 March 2009 were extracted from the Australian New Zealand Clinical Trials Registry and ClinicalTrials.gov. A regression model was used to identify factors associated with industry sponsorship. MAIN OUTCOME MEASURES: The proportion of cancer trials compared with estimated burden of disease for each cancer. RESULTS: There were 368 interventional cancer trials open to recruitment. The most-researched cancer was breast cancer, accounting for 17% of trials. Only 7% of trials were in lung cancer, yet lung cancer is responsible for the greatest burden of disease. Industry was the primary sponsor in 43% of trials. Drug treatments were tested in most trials (69%). Trials were more likely to be industry sponsored if they tested systemic rather than local treatments (OR, 16.71; 95% CI, 4.70-59.43), included patients with advanced rather than early disease (OR, 3.76; 95% CI, 1.78-7.94) and used random rather than non-random allocation (OR, 1.78; 95% CI, 1.06-3.00). CONCLUSION: There is variation in the number of trials according to cancer site, with some cancers being underrepresented relative to their burden of disease. Industry sponsorship is more likely for trials that investigate systemic therapy, recruit patients with advanced disease and are randomised.