The formation of magnetic domains in epitaxially grown Co and Fe films is investigated by spin-polarized scanning electron microscopy. Classical theories predict single domain behavior in very thin films. However, ultrathin Co/Au(111) and Fe/Cu(100) films show out-of-plane domains of micron size, whereas Co/Cu(100) films grow in a single domain state. We will discuss these results and also show how surface anisotropies in these films can be deduced by following the switching of the magnetization direction from out-of-plane to in-plane. © 1992.