Disclosed is a split tip catheter having a tapered venous lumen and a tapered arterial lumen, wherein each of the lumens includes a D-shaped cross section. In one embodiment, the length of the venous lumen is greater than the length of the arterial lumen. The venous lumen and the arterial lumen are secured in a side-by-side configuration via an outer sleeve such that the proximal end of the outer sleeve is aligned with the proximal ends of the venous lumen and the arterial lumen, leaving the distal ends of the venous lumen and the arterial lumen free. The proximal ends of the outer sleeve, the venous lumen, and the arterial lumen are insert molded to a hub to connect the lumens to extensions such as venous and arterial blood lines for dialysis treatments.
