This chapter throws light on spin-dependent conduction and spin manipulation. When placed in an electric field, the spin up and spin down electrons exhibit different mobility, resistivity and henceforth different conductivities. This is especially important for ferromagnetic materials which possess asymmetric band structure for spin-up and spin-down electrons. Spin can explain the resistivity of ferromagnetic (FM) metals at the Curie temperature. Further, the phenomena of Tunnel magnetoresistance (TMR) has been observed in heterojunction layers comprising of an insulating tunnel barrier sandwiched in between the two different FM metal layers and are utilized in the fabrication of Magnetic Tunnel Junctions (MTJ) and Multiferroic Tunnel Junctions (MFTJs). Another spin-dependent phenomenon is the spin-hall effect which finds origin in charge-spin coupling due to spin-orbit interaction. Further, it is observed that the multiphase systems comprising of alternating FM-nonmagnetic (conductive) interlayers exhibit Giant magnetoresistance (GMR). This chapter concludes with spintronic devices which utilize the manipulation of ‘spin polarised electrons’ in order to obtain the non-equilibrium of the spin up or/and spin-down electrons. Spintronic devices find applications in spin-based non-volatile digital logic devices, spin Field Effect Transistors, etc.