Femtosecond (fs = 10−15 sec.) laser ablation of Si(100) with thermally grown oxide films was studied with pump/probe imaging techniques in order to determine the role of film thickness on ablation dynamics. Two different imaging geometries were used in this study. Front view images were formed with the reflection of a delayed probe pulse from the area of a sample irradiated with a pump pulse. By changing the delay between the pump and probe pulses, images were obtained showing the evolution of the surface as a function of time (0 – 12 ns after the arrival of the pump pulse). The side view imaging technique, also known as shadowographic imaging, an image was formed of a delayed probe pulse which passed through the ablation plume produced by a pump pulse parallel to the sample surface. Both laser induced shock wave propagation and material removal were observed to change with increased thermal oxide thickness.