Flight simulators are examples of virtual environment (VE) systems that often give rise to a form of discomfort resembling classical motion sickness. The major difference between simulator sickness and other forms of motion sickness is that the former exhibits more oculomotor-related symptoms and far less actual vomiting. VEs of the future are likely to include more compellingly realistic visual display systems, and these systems can also be expected to produce adverse symptoms. The implications of simulator sickness for future uses of VEs include adverse consequences for users' safety and health, user acceptance, training effectiveness, and overall system performance. Based on data from a factor analysis of over 1000 Navy and Marine Corps pilot simulation exposures, a new scoring procedure for simulator sickness has recently been developed (Lane & Kennedy, 1988; Kennedy, Lane, Berbaum, & Lilienthal, 1992). The factor analytic scoring key provides subscales for oculomotor stress (eyestrain), nausea, and disorientation. Simulators are being examined in terms of these factor profiles to identify causes of simulator sickness. This approach could also be used in evaluating motion sickness-like symptomatology that occurs in connection with the use of VEs. This paper describes the use of the multifactor scoring of the Simulator Sickness Questionnaire (SSQ) in diagnosing sources of simulator sickness in individual simulators. Reanalysis by this new methodology was employed to standardize existing simulator sickness survey data and to determine whether relationships existed that were missed by the more traditional scoring approaches.