We present results of the design, fabrication, and testing of a microfabricated, membrane-type magnetic actuator. Magnetic pieces made of electroplated Permalloy (Ni₈₀Fe₂₀) are embedded in a thin flexible membrane made of silicone elastomer. When an external magnetic field is applied, a torque generated on the magnetic pieces produces membrane displacement. Permalloy pieces that are 100-μm-wide, 870-μm-long, and 22-μm-thick are strategically positioned in a 2-mm-square, 40-μm-thick polydimethylsiloxane (PDMS) membrane (Sylgard 184). This design, produced through numerical simulations, is optimized to realize large membrane displacements. Tests performed on this membrane actuator showed displacements >80μm in the presence of a 2.85×10⁵A/m external magnetic field. Larger displacements are possible with greater magnetization fields. This type of membrane actuator can be applied to the fabrication of tetherless micropumps for use in microfluidic systems.