In this report, excimer laser annealed polycrystalline silicon (poly-Si) films on flexible polymer substrates are investigated. The amorphous silicon (a-Si) films were first deposited on polycarbonate (PC) and polyethersulfone (PES) substrates by radio-frequency (RF) magnetron sputter and sequentially annealed by XeCl excimer laser annealing system (λ = 308 nm). The argon concentration of a-Si films which was estimated by Rutherford Backscattering Spectrometry (RBS) was found to be dependent on the dynamic pressure during the deposition process and the sputtering gas. Typically, the argon concentration of a-Si film was 1 ∼ 2% when the film was deposited using argon gas at 6 mTorr. After the annealing process, the average grain size of the poly-Si film annealed with laser energy density of 289 mJ/cm2 was 400 nm estimated from transmission electron microscope (TEM) investigations.