This study demonstrates the feasibility of obtaining structural topology and helical tilt information of an integral transmembrane helix inserted into aligned planner-supported phospholipid bilayers (mechanically aligned bilayers) using a spin-label EPR approach. Significant changes are observed in the hyperfine splitting values at various orientations of the spin-labeled transmembrane helix with respect to the static magnetic field (B-0). The hyperfine splitting values gleaned from the orientational dependent EPR spectra allow the helical tilt of the transmembrane helix to be determined.