We present results of three-dimensional MHD simulations of reconnection in the near-Earth plasma sheet. We use two-dimensional start configurations which include the Earth's dipole field explicitly and three-dimensional resistivity profiles. These equilibria are stable against large-scale tearing instability, that is, the mode with the maximum growth rate. For nonhomogeneous resistivity profiles, however, the system may become unstable against nonlinear, resistive modes. We discuss onset and nonlinear evolution of reconnection due to these instabilities. One result of our three-dimensional simulations is that earthward flow can be found even tailward of the reconnection region. This confirms a typical feature of previous two-dimensional simulations of reconnection in the near-Earth plasma sheet. The nonlinear resistive instabilities found in our simulations could be relevant for phenomena like pseudobreakups. ¿ American Geophysical Union 1996