  We found quasinormal modes, both in time and frequency domains, of the Ernst
black holes, that is neutral black holes immersed in an external magnetic
field. The Ernst solution reduces to the Schwarzschild solution, when the
magnetic field vanishes. It is found that the quasinormal spectrum for massless
scalar field in the vicinity of the magnetized black holes acquires an
effective "mass" $\mu = 2 B m$, where m is the azimuthal number and B is
parameter describing the magnetic field. We shall show that in the presence of
a magnetic field quasinormal modes are longer lived and have larger oscillation
frequencies. The perturbations of higher dimensional magnetized black holes by
Ortaggio and of magnetized dilaton black holes by Radu are considered.
