A micro alternating tangential flow (microATF) perfusion filter includes a hollow cylinder having a proximal end and a distal end. The proximal end is connected in series to a permeate chamber, followed by a retentate chamber. The proximal end either (i) terminates in or at the permeate chamber, or (ii) terminates in or at the retentate chamber. The portion of the proximal end within the permeate chamber, in a case of (ii), possesses at least one opening allowing fluid communication between an inside of the hollow cylinder and the permeate chamber. The microATF perfusion filter further includes an inlet, positioned over the retentate chamber, for communication with a source of positive or negative pressure, and an outlet, positioned in a wall of the permeate chamber, which can be connected to a check valve, which, in turn, can be connected to a hydrophobic fluid vent filter.