The crossflow microfiltration of a 30% (w/w) water-in-oil emulsion is reported, using kerosene as the organic phase and hydrophobic PTFE membranes, with a mean pore size of 0.2 mum. The flux performance of corrugated membranes is compared with that of flat membranes and shows that a marked enhancement in flux is obtained with corrugated membranes. The influences of crossflow velocity, flow channel height and transmembrane pressure on flux rate are reported. The effect of varying the angle of corrugations on the overall flux performance is also examined. Measurement of mass transport rates at corrugated solid surfaces, using the limiting current technique, are reported and correlated in terms of channel Reynolds number. The mass transport rate and membrane flux rate show a similar dependency on crossflow velocity and Reynolds number.