A new mechanical test apparatus for the evaluation of liquid penetration of barrier fabrics has been developed. The apparatus is similar to that used for ASTM Standard Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Synthetic Blood Using a Mechanical Pressure Technique (F 1819), with a few important differences. The test material is compressed between a pool of liquid and a solid surface. This apparatus is used without a sponge for retaining the challenge liquid. Additionally, any desired pressure profile may be programmed into a computer, and used for testing. Four materials were evaluated using this apparatus, and the results were compared to those obtained by hydrostatic testing using a modified ASTM Standard Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Synthetic Blood (F 1670). Breakthrough pressures were higher for mechanical testing than for hydrostatic testing. Pressures obtained using an electronic sensor were not significantly different than those obtained using visual detection. Pressure ramp rates appear to have some effect on visually detected breakthrough pressures, but no significant effect on pressures obtained by viral assay.