We designed a novel monomer bearing one organosiloxanyl group and two amide groups in order to improve its compatibility with hydrophilic vinyl monomers. The novel monomer, N-2-(N',N'-dimethylcarbamoyl)ethyl-N-[3-tris(trimethylsiloxy)silylpropyl ]acrylamide (SiDAAA) showed good miscibility with N-(hydroxyethyl)acrylamide (HEAA) and formed a transparent hydrogel with 2-hydroxyethyl methacrylate (HEMA) in the presence of a crosslinker. In contrast, the conventional monomer did not show transparency, such as tris(trimethylsiloxy)silylpropyl methacrylate (TRIS). These results validated our monomer design concept.