A multilumen catheter assembly 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 circular shape in cross section and is attached to the at least two distal end tubes. In one embodiment, the catheter assembly may be made by extruding a unitary tube having internal longitudinally extending lumens, then splitting the unitary tube at a distal end portion of the unitary tube to form the at least two distal end tubes. The at least two distal end tubes are then ground and polished. In another embodiment, the catheter assembly may be made by extruding the at least two distal end tubes and permanently bonding proximal ends thereof to form the unitary portion.