The velocity profile inside cylindrical microchannels of diameters less than 50 microns is presented. Silica microchannels were fabricated using a novel technique† in order to investigate the effect of the surface characteristics on the velocity profile inside microchannels and in particular, within a region near the channel surface. Cylindrical channels containing abrupt contractions were used to investigate the velocity profiles resulting from changes in surface properties in pressure-driven entry flows over a range of applicable length-scales. The results were be compared to simulations using CFD-Ace, a computational fluid dynamics package for microfluidics that can account for surface properties, including hydrophobicity.