Mitral valve (MV) haemangiomas are rare primary cardiac tumours which may cause progressive cardiac failure as well as sudden death. We present a case of a 44-year-old woman referred for surgical correction of symptomatic severe mitral regurgitation. Preoperative two-dimensional transthoracic and transoesophageal echocardiography (TOE) were reported as demonstrating complex bi-leaflet prolapse causing severe mitral regurgitation. The patient was listed for MV surgery. Only on preoperative CT coronary angiogram was a filling defect noted, leading to suspicion of a cardiac tumour. Prior to skin incision, three-dimensional (3D) TOE revealed a 2×3 cm mass attached to the anterior leaflet of the MV. The tumour was subsequently resected, and the MV replaced. Postoperative histopathology confirmed a large cavernous haemangioma of the anterior MV leaflet. This case highlights a rare cause of severe mitral regurgitation and demonstrates the utility of 3D TOE as an adjunctive modality in confirming the suspected diagnosis of a cardiac tumour.