The existence of an intrinsic magnetic field at Mars has yet to be ascertained despite a number of missions to Mars over the last few decades. It is now widely accepted that the thermal pressure of the Martian ionosphere is not large enough to balance the average solar wind dynamic pressure, therefore the ionosphere must be magnetized, either by a solar wind induced field or by an intrinsic field. Shinagawa and Cravens (1980) demonstrated that the behavior of the Martian ionosphere depends on the strength of the intrinsic field. We have improved our earlier model of the Martian ionosphere by allowing the magnetic field to have any direction in the horizontal plane, and we present results of calculations for several different intrinsic magnetic field strengths and directions. When the solar wind dynamic pressure exceeds the Martian ionospheric thermal pressure, the plasma motion is weakly downward throughout the ionosphere for the case of no intrinsic magnetic field, but when the intrinsic and induced fields are in opposite directions, the plasma flow tends to converge toward the current sheet. As a consequence of this convergence, the plasma density is somewhat enhanced near the current sheet, which is located near an altitude of 170 km. The ionosphere above an altitude of about 190 km is not significantly affected by the existence of an intrinsic field as weak as 60 nT. In order to unambiguously determine the magnitude of an intrinsic field on the dayside of Mars, it will be necessary to make magnetic field measurements below an altitude of 200 km. ¿ American Geophysical Union 1992