Semi-solid casting is one of the new methods of manufacturing metalic parts. In many semisolid casting methods, the parts are produced by applying shear to a solidifying melt to make a slurry of suspended non dendritic primary particles in the melt. Most popular semi-solid casting processes involve two stages. The first stage includes producing a semi-solid slurry which is formed in a high strength metallic die in the second stage of the process. Because of high pressures applied on the semi-solid slurry during the second stage, the die should be made of expensive alloy steels. Also most of the studies have been conducted on low melting point alloys such as aluminium or magnesium and high melting point alloys have attracted less attention. Gray cast iron is a high melting point alloy used in many industrial applications and is suitable for products requiring good heat transfer, machinablity, damping capacity and wear resistance. By increasing the carbon content, flake graphites in the microstructure become coarser and mechanical properties are reduced. Therefore, reducing the size of flake garphite in high carbon cast irons may results in superior physical and mechanical properties. This research investigated the possibility of low cost single stage semi solid casting of a high melting point alloy, i.e. gray cast iron, in sand molds using centrifugal force. For this purpose, a specially designed runner chilled sand mold rigged to a vertical centrifugal casting machine was used. The hypereutectic gray cast iron was poured in the sand mold at 1270, 1275 and 1285 ?C and at rotation speeds of 200 and 400 rpm. The effects of different parameters on microstructure as well as mechanical and physical propertie of the specimens were characterized. In order to compare the results, control samples were cast in the same mold at 1275 ?C by traditional methods of gravity and centrifuged casting. Mold filling and temperature and solid fraction changes during solidification were also simulated by Procast simulation software. The results showed that the average length and thickness of eutectic and Kish flake graphites in semi-solid centrifuged castings were smaller than those in the castings prepared by conventional gravity or centrifuged casting methods. Reducing the pouring temperature in semi-solid casting method led to smaller size and thickness of eutectic and Kish graphite flakes. Hardness and tensile strength of the semi-solid cast samples were higher than those of the control samples. Improvment of the microstructure by semi-solid casting resulted in increase of tensile strength and hardness of control samples from 128 MPa and 166 vickers, respectively, to 154 MPa and 192 vickers for semi-solid samples, respectively. The result showed that semi solid casting of hypereutectic gray cast iron in sand mold using the new single stage semi solid centrifuged casting method was successful. Key words: Centrifuged Semi-Solid Casting, Hypereutectic Gray Cast Iron, Kish graphite, Sand Mold, Mechanical peroperties, Simulation