Microfiltration is a form of filtration that has two common forms. One form is crossflow separation. In crossflow separation, a fluid stream runs parallel to a membrane. There is a pressure differential across the membrane. This causes some of the fluid to pass through the membrane, while the remainder continues across the membrane, cleaning it. The other form of filtration is called dead-end filtration or perpendicular filtration. In dead-end filtration, all of the fluid passes through the membrane, and all of the particles that cannot fit through the pores of the membrane are stopped.

Crossflow microfiltration is used in a number of applications, as either a prefiltration step or as a process to separate a fluid from a process stream.