A series of four well-defined poly(ferrocenyldimethylsilane) (PFS) samples spanning a molecular weight range of approximately 10,000-100,000 g mol(-1) was synthesized by the living anionic polymerization of dimethyl[1]silaferrocenophane initiated with n-BuLi. The polymers possessed narrow polydispersities and were used to characterize the solution behavior of PFS in tetrahydrofuran (THF). The weight-average molecular weights (M-w) of the polymers were determined by low-angle laser light scattering (LALLS), conventional gel permeation chromatography (GPC), and GPC equipped with a triple detector (refractive index, light scattering, and viscosity). The molecular weight calculated by conventional GPC, with polystyrene standards, underestimated the true value in comparison with LALLS and GPC with the triple detection system. The Mark-Houwink parameter a for PFS in THF was 0.62 (k - 2.5 x 10(-4)), which is indicative of fairly marginal polymer-solvent interactions. The scaling exponent between the radius of gyration and M-w was 0.54, also consistent with marginal polymer-solvent interactions for PFS in THF.