<p class="AMSmaintext">Shape and direction of gate in centrifugal casting affected the microstructures and defects in castings. The purpose of this research was to determine the effects of gate shape and direction in centrifugal casting toward on porosity, density, roughness, and microstructures on the artificial lumbar disc model. The main shapes of the gate were circular and rectangular cross-section.  The circular cross-section gate shape was used for two different directions of artificial lumbar discs; vertical, and horizontal. Furthermore, the rectangular cross-section gate shape consisted of three different directions; oblique clockwise, oblique counter-clockwise and perpendicular towards the mold. The rotational mold was conducted at a speed of 60 rpm. The results showed that the rectangular cross-section gate shape with the oblique direction same with the rotation of the mold produced artificial lumbar disc model that had the smallest porosity area among the other directions. It was the best shape and direction of the gate among the others which had the smallest porosity area (0,68%), highest density (4,517 g/cm³), and smoothest roughness (8,76 µm). In the sub-surface, the microstructure of α-case was formed. The thickness and hardness of the α-case in this design were 50-100 µm and 760 VHN, respectively. Hence, the rectangular cross-section gate shape with the oblique direction same with the rotation of the mold was appropriate to be applied in the manufacture of an artificial lumbar disc model.</p>