This article reviews the recent advances of epitaxial ferromagnetic thin films and heterostructures as well as devices towards semiconductor-based spin-electronics or often called spintronics. We review the developments of III-V based ferromagnetic thin films and heterostructures grown by molecular beam epitaxy, with focus on the Mn-delta-doped GaAs/p-AlGaAs heterostructures with high ferromagnetic transition temperature, and control of the spin-dependent properties. As a new direction in spintronics research, we present our recent study on a new silicon-based spin device, spin metal-oxide-semiconductor field-effect transistor (spin MOSFET), and novel reconfigurable or reprogrammable logic gates using spin MOSFETs, which are compatible with the current CMOS technology and promising for reconfigurable computing. Crown Copyright © 2005 Published by Elsevier B.V. All rights reserved.