4185 Phystech, provisional designation 1975 ED, is a Florian or background asteroid from the inner regions of the asteroid belt, approximately 6 kilometers in diameter. It was discovered on 4 March 1975, by Soviet astronomer Tamara Smirnova at the Crimean Astrophysical Observatory in Nauchnij, on the Crimean peninsula. The presumed S-type asteroid has a rotation period of 4.67 hours. It is named in honor of the Moscow Institute of Physics and Technology ("PhysTech") on its 50th anniversary.