The present invention is directed to a non-immunogenic cellular composition comprising: a cell having a cell surface and antigenic determinants on the cell surface; an optional linker molecule covalently attached to the cell surface; and a hydrophilic, biocompatible, non-immunogenicity providing compound or polymer (e.g., polyethylene glycol or a derivative thereof) covalently attached to the linker molecule or directly to the cell. In one embodiment, the linker molecule is covalently attached directly to the antigenic determinant on the cell surface. In an alternate embodiment, the linker molecule may be covalently attached to a non-antigenic site on the cell surface, but will camouflage the antigenic determinant on the cell surface. Various uses of the resulting non-immunogenic cell are also provided, including a method of decreasing phagocytosis of a cell, a method of decreasing an adverse reaction to a transfusion, a method of decreasing rejection of a transplanted cell, tissue or organ, and a method of decreasing antibody-induced aggregation of cells.