Deposit build-up is the most serious constraint in crossflow microfiltration processes since it leads to a significant decrease in permeate flux. Therefore, controlling deposit build-up is necessary for membrane process optimisation. The use of a model suspension of clay (bentonite) and an optical measurement technique for deposit thickness makes it possible to characterise the proper-ties of the deposit and the conditions under which it builds-up. This study investigates the relationship between permeate flux and the filtration conditions affecting the deposit build-up. It shows that for specific operating conditions, permeate flux can be stabilised and that cake formation is substantially avoided. For the highest crossflow velocity tested, 88% of the mass carried by convection to the membrane surface is swept away by the tangential flow.