The reaction between the monohydroxylated cyclotriphosphazene (4-hydroxyphenoxy)pentaphenoxycyclotriphosphazene, 3-obtained by the reaction of the (4-methoxyphenoxy)pentaphenoxy-cyclotriphosphazene 2 with BBr3/H2O-and methacryloyl chloride, led to a new methacrylate-substituted cyclotriphosphazene, 4. Radical polymerization of 4 led to the hybrid inorganic-organic poly(cyclophosphazene-methacrylate) 5. The structures of both classes of compounds were investigated by P-31, C-13, and H-1 NMR, infrared spectroscopy, mass spectrometry, size exclusion chromatography, and elemental analysis. The thermal behavior of the new polymer 5 was investigated and compared to the one of poly(phenyl methacrylate) 6. It was demonstrated that the incorporation of cyclophosphazene as pendant group increases the thermal stability of the corresponding organic polymer. The free-radical promoted grafting of 5 onto poly(vinyl alcohol)surface has been described. The resultant surfaces were studied by ATR-IR, XPS, and contact angle techniques. It was demonstrated that the presence of ethyl functions in 5 increases the grafting yield.