This paper describes a series of microstructural and strength studies performed on hypereutectic cast iron which was sand cast using a variety of end chills (metallic, non-metallic, water cooled and liquid nitrogen cooled, respectively). The effects of cooling rate on the dendrite arm spacing (DAS) and the ultimate tensile strength (UTS) were evaluated. Attempts were also made in the paper to explain these effects and to correlate the UTS with the DAS.