Expressions for group and phase velocity are derived for left‐ and right‐hand circularly polarized waves propagating along the static magnetic field of a magnetoplasma composed of electrons, positive ions, and negative ions. It is shown that a small percentage of negative ions can have pronounced effects on the propagation characteristics of the right‐hand wave near the negative ion gyrofrequency. In particular, the wave becomes evanescent in a frequency band just above the gyrofrequency, exhibits a ‘nose effect’ below the gyrofrequency, and above the stop band the wave's group velocity is strongly influenced by the negative ions. Some experimental observations consistent with negative ion effects are