Pressure drop (Ap) was measured while PET (280degreesC, 330 Pa(.)s) or LDPE (160degreesC) was flowing through polymer (fiber) filtration-grade (i) single filter gauze, (ii) packets of 2-55 identical filter gauzes, and (iii) packet of 7 gauzes (64, 400,1600, 6400,12000, 16900 and 24400 openings/cm(2)). At shear rates of 2-800 s(-1) in the packet, LDPE was a non-Newtonian, and PET was a Newtonian fluid. At a single gauze, Deltap was 117% of that at one identical gauze in the packet of more than 10 gauzes. In case iii, the observed K-values in the equation Deltap = K (rate per empty fitter)(viscosity), were 76-88% of the K-values calculated by summing single-gauze K's. For non-Newtonian fluids, the drag coefficient lambda = 41/( Reynolds number).