Finite concentration inverse gas chromatography (i.g.c.) was used to determine the crosslink density of three poly(dimethylsiloxane) (PDMS) samples, which were crosslinked with different doses Of gamma-rays. Crosslink density data of the same materials were also obtained in swelling measurements and, in one case, in stress-strain mechanical analysis. Results yielded by the different techniques agreed very well considering the different nature of the approximations made in the various experiments. Information obtained by i.g.c. also included the Flory-Huggins interaction parameters of the linear and crosslinked PDMS samples.