A multilumen catheter assembly is provided, which includes a unitary portion and at least two distal end tubes extending distally from the unitary portion. The unitary portion includes an exterior having a generally round or oval shape in cross section and includes at least two distal end tubes of generally circular (or other) cross sectional shape extending longitudinally therethrough. The catheter assembly may be made by extruding a unitary tube having internal longitudinally extending lumens (of circular or other shape), then splitting the tube on its distal end portion to form distal end tubes. The tubes are then ground and polished, the finished tubes retaining in combination the generally oval cross sectional shape of the unitary extrusion, or the finished tubes can each be finished to a circular, or other, cross sectional shape; or the finished tubes could include a combination of cross sectional shapes over its longitudinal length.