Four groups of 37 subjects each (highly susceptible men, highly susceptible women, nonsusceptible men, and nonsusceptible women) were obtained from a population of 2,432 college students ranging in age from 18 to 39 years. Susceptibility to motion sickness was determined by scores on a motion sickness questionnaire (MSQ); only individuals with extreme scores were considered for inclusion in the experimental groups. The following tests were administered: Floor Ataxia Test Battery, State-Trait Anxiety Inventory, Menstrual Distress Questionnaire, Cornell Medical Index, Cornell Work Form, Eysenck Personality Inventory, Rotter Internal-External Locus of Control Scale, and the 16 Personality Factors test. Each subject was tested on at least three, but not more than six, of the eight tests. Significant sex differences were obtained on the ataxia battery and the Cornell Medical Index. Susceptible subjects did not differ significantly from nonsusceptibles on the ataxia battery but did differ significantly on all personality tests except the Menstrual Distress Questionnaire (administered only to women) and the Rotter Scale. The generally consistent and significant patterns of results from the psychological tests probably reflect the selection factors used in defining the subject groups; certain personality characteristics are associated with a high degree of susceptibility to motion sickness.