A mathematical model is presented for predicting the shear-induced decrease in live cells occurring over time during tangential flow filtration. The model uses a cell death rate constant (K) and considers the effects of flow rate, solution viability, and filtration system volumes and dimensions. Single pass and recycle capillary experiments with solutions of high (93%), medium (87%), and low (70%) viability were run, where the maximum laminar shear stress ranged from 10-300 Pa, to validate the model and determine cell death rate constants. The K values for the suspended CHO cells used in this research ranged from 0.06 to 12.5 s(-1). These K values increased with shear stress, as expected, and also as the solution viability decreased.