This paper investigates pressure driven liquid flow through round and square microchannels fabricated from fused silica and stainless steel. Pressure drop data are used to characterize the friction factor for channel diameters in the range 15-150 mum and over a Reynolds number range 8-2300. Distilled water, methanol, and isopropanol were used in this Study based on their distinct polarity and viscosity properties. Distinguishable deviation from Stokes flow theory was not observed for any channel cross-section, diameter, material, or fluid explored.