A 38-year-old-female presented to our unit for investigation of an incidental diagnosis of right ventricular dilatation. Transthoracic colour Doppler echocardiography demonstrated an anomalous flow into the inferior vena cava. The suspicion of partial anomalous venous drainage was supported by the finding of a scimitar sign on chest X-ray. Left and right heart catheterization demonstrated a significant left-to-right shunt (Qp/Qs = 2.22) with a step-up in oxygen saturation from the inferior vena cava (IVC) to lower right atrium. Selective angiography confirmed drainage of an anomalous pulmonary vein to the IVC-atrial junction. Scimitar syndrome is a rare vascular anomaly that can manifest in childhood with signs of right heart failure and/or recurrent pneumonia. When asymptomatic, this anomaly can be accidentally discovered in adulthood and should be suspected in cases of left-to-right shunt without evidence of obvious cardiac structural defects.