Importance: Randomised trials have shown that catheter ablation (CA) is superior to medical therapy for ventricular tachycardia (VT) largely in patients with ischaemic heart disease. Whether this translates to patients with all forms and stages of structural heart disease (SHD—e.g., non-ischaemic heart disease) is unclear. This trial will help clarify whether catheter ablation offers superior outcomes compared to medical therapy for VT in all patients with SHD. Objective: To determine in patients with SHD and spontaneous or inducible VT, if catheter ablation is more efficacious than medical therapy in control of VT during follow-up. Design: Randomised controlled trial including 162 patients, with an allocation ratio of 1:1, stratified by left ventricular ejection fraction (LVEF) and geographical region of site, with a median follow-up of 18-months and a minimum follow-up of 1 year. Setting: Multicentre study performed in centres across Australia. Participants: Structural heart disease patients with sustained VT or inducible VT (n=162). Intervention: Early treatment, within 30 days of randomisation, with catheter ablation (intervention) or initial treatment with antiarrhythmic drugs only (control). Main outcomes, measures, and results: Primary endpoint will be a composite of recurrent VT, VT storm (≥3 VT episodes in 24 hrs or incessant VT), or death. Secondary outcomes will include each of the individual primary endpoints, VT burden (number of VT episodes in the 6 months preceding intervention compared to the 6 months after intervention), cardiovascular hospitalisation, mortality (including all-cause mortality, cardiac death, and non-cardiac death) and LVEF (assessed by transthoracic echocardiography from baseline to 6-, 12-, 24- and 36-months post intervention). Conclusions and Relevance: The Catheter Ablation versus Anti-arrhythmic Drugs for Ventricular Tachycardia (CAAD-VT) trial will help determine whether catheter ablation is superior to antiarrhythmic drug therapy alone, in patients with SHD-related VT. Trial Registry: Australian New Zealand Clinical Trials Registry (ANZCTR) Trial Registration ID: ACTRN12620000045910 Trial Registration URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377617&isReview=true