Further results from an experimental study of membrane fouling and permeate flux decline during crossflow microfiltration are presented. A computer controlled microfilter and a variety of well characterised particulate solids and polymeric membranes were used to acquire a range of data over typical operating conditions. Example data highlight influences of the process parameters filtration pressure, crossflow velocity, suspension concentration, and particle surface charge, and demonstrate the interdependence of the process operating conditions with particle size, size distribution and shape. Many of the results obtained are discussed with respect to existing literature data which are apparently contradictory, but the current data provide explanations for these contradictions and enable conclusions to be drawn.