"Simulator Sickness" describes a symptom complex frequently reported by pilots during or after flight simulator training. There were 112 helicopter pilots at a U.S. Army AH-1 Cobra Flight Weapons Simulator (FWS) who completed a symptom-oriented subjective questionnaire. Of these, 40% reported symptoms of dysequilibrium; pilots developing simulator sickness had significantly more total and AH-1 flight time. Adaptation to the syndrome occurred with increasing FWS experience. The history and aeromedical significance of simulator sickness are briefly reviewed, and a case report presented. A mandatory grounding policy in use locally is described. Potential treatment strategies are briefly discussed.