Laboratory experiments using a sodium plasma are reported that demonstrate a robustness of electrostatic ion-cyclotron waves in the presence of elevated neutral-helium pressure. It is found that the excitation threshold decreases with neutral pressure, and that, in the presence of a transverse localized electric field, the waves are able to tolerate much higher collisionality than previously believed. When the ion-neutral collision frequency and ion gyrofrequency are comparable, the excitation threshold is significantly smaller than its collisionless value. ¿ 1998 American Geophysical Union