A disposable micropump is presented that uses the piston actuation principle and relies on the magnetic properties of a ferrofluid, a colloidal suspension of nanosize ferromagnetic particles. The cost effective micropump consists of 7 bonded layers of polymethylmetacrylate (PMMA) that are either micromachined or structured by powder blasting. Two silicone check-valves are also integrated in the microchip. External dimensions of our prototype are 36 mm x 22 mm x 5 mm. The magnetic liquid plug is externally actuated by a motorized permanent magnet. Water has been successfully pumped at a flow rate of 30 µL/min without backpressure; pumping is demonstrated up to a backpressure of 25 mbar.