The laser-induced damage (LID) thresholds of fused silica and single crystal NaCI were studied at wavelengths of 0.5 and 1µm for pulses as short as 4 ps for a variety of focal spot sizes. The problem of sample-to-sample variation was minimized by performing parametric studies on a single sample at a time. Beam distortion measurements and polarization dependence studies of the LID thresholds demonstrate that the contribution of self-focusing to the LID measurements in this work was negligible. The damage threshold field EB was found to increase as the pulsewidth was decreased in both materials at both wavelengths. The strongest pulsewidth dependence observed was approximately an inverse square root proportionality observed in NaCI at 1 µm for pulses shorter than 10 ps. For conditions of equal pulsewidth and the same focal spot size, EB was less at 0.5 um than at 1 um for both materials.