Polyindene was prepared by the controlled cationic polymerization of indene initiated with cumyl methyl ether/TiCl4 in CH2Cl2 at -65°C. The number-average molecular weight was controlled by the ratio of monomer to cumyl methyl ether; polydispersity indicies ranged from 1.8 to 3. Polyindene samples prepared by this technique were characterized by 1H and 13C NMR spectroscopy, and a corrected assignment of chemical shifts in these spectra was made with respect to previous literature reports. Polyindene samples ranging from Mn = 5 to Mn = 70 kg/mol were hydrogenated to high levels of phenyl ring saturation using a heterogeneous catalyst consisting of silica-supported Pt. Characterization of polyindene and its hydrogenation product by size exclusion chromatography using a light-scattering detector showed that the hydrogenation proceeded without change in the degree of polymerization. The relationship between molecular weight and the glass transition temperature for these polymers was established, and Tg values of 207°C for polyindene and 268°C for hydrogenated polyindene were predicted in the limit of infinite molecular weight.