Nitrated and aminated polycarbonates were prepared chemically, characterized and tested in vitro as a possible biomaterial. Adhesion of Staphylococcus aureus NCIM 5021, Escherichia coli NCIM 2931 and Proteus vulgaris NCIM 2813 and the presence of carbohydrate, protein, CFU and ATP on these surfaces were examined. Cytotoxicity of these surfaces was investigated by growing L929 mouse fibroblast cells. NO₂-PC was more hydrophilic than un-PC and reduced adhesion of bacterial protein and carbohydrate. NH₂-PC was the most hydrophilic surface biofilm prevention and increased proliferation of the fibroblast cells. The motility of all the three organisms decreased on aminated surface when compared to that on the other two. This study indicated that reducing the surface hydrophobicity alone was not sufficient to develop a biocompatible material, but providing favorable surface functional groups was also a   necessary criterion. A strong correlation was observed between the hydrophobicity of the polymer surface and the zeta potential of the organism with bacterial attachment (CFU/ml). A multi-linear regression model with these two parameters was able to fit the observed bacterial attachment data well.