  We present a linear analysis of the stability of accretion disks in which
angular momentum is removed by the magnetic torque exerted by a centrifugally
driven wind. The effects of the dependence of the wind torque on field strength
and inclination, the sub-Keplerian rotation due to magnetic forces, and the
compression of the disk by the field are included. A WKB dispersion relation is
derived for the stability problem. We find that the disk is always unstable if
the wind torque is strong. At lower wind torques instability also occurs
provided the rotation is close to Keplerian. The growth time scale of the
instability can be as short as the orbital time scale. The instability is
mainly the result of the sensitivity of the mass flux to changes in the
inclination of the field at the disk surface. Magnetic diffusion in the disk
stabilizes if the wind torque is small.
