A microfluidic device was fabricated via photolithographic techniques which can create transient elongational and shear forces ranging over three orders of magnitude while still maintaining laminar flow conditions. The contractional fluid flow inside the microfluidic device was simulated with FLUENT (a computational fluid dynamics computer program) and the local deformation forces were characterized with the scalar quantity, local energy dissipation rate. The sensitivities of four cell lines (CHO, HB-24, Sf-9, and MCF7) were tested in the device. The results indicate that all four cell lines are able to withstand relatively intense energy dissipation rates (up to 104–105 kW/m3), which is orders of magnitude higher than the maximum local energy dissipation rates generated by impellers in bioreactors, but comparable to that associated with small bursting bubbles. While the concept that suspended animal cells are relatively robust with respect to purely hydrodynamic forces in bioprocess equipment is well known, these results quantitatively demonstrate these observations. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 80: 428–437, 2002.