The aim of this study was to prepare transparent polystyrene (PSt) hybrid materials containing silicone macromonomer. Silicone urethane methacrylate (SiUMA) was synthesized by the reaction between the hydroxyl end groups of a silicone macromonomer and the isocyanate group of 2-methacryloyloxyethyl isocyanate, (MOI), and copolymers with different weight proportions were prepared by copolymerization of styrene (St), SiUMA and ethyleneglycol dimethacrylate (EGDMA). Though the prepared P(St-co-SiUMA) copolymers which had not introduced EGDMA were opaque, the prepared P(St-co-SiUMA-co-EGDMA) copolymers were transparent, similarly to pure PSI. DSC and H-1-NMR measurements were carried out to investigate the factors in this transparency in detail. From these measurement results, it was confirmed that the reactivity of the copolymerization had a significant influence on the transparency of the product. In addition, the contact angle of P(St-co-SiUMA-co-EGDMA) with 10 wt % SiUMA was greater than 90 degrees, which was a 10 degrees improvement compared to pure PSI. (c) 2007 Wiley Periodicals, Inc.