Diagnosis of Asperger's Syndrome (AS) in adults is difficult, and clinical sample-based studies that systematically illustrate the clinical characteristics of adult AS patients are needed so that appropriate treatment can be provided. Here we examined the clinical characteristics of AS in 112 adults (median age, 28.0 years [range, 18-52]; 71 men and 41 women), 55 AS group (median age, 27.0 years [range, 18-49]; 36 men and 19 women), 57 control group (median age, 28.0 years [range, 20-52]; 35 men and 22 women) through administration of the Japanese version of the Autism-Spectrum Quotient (AQ) and the Japanese version of the Schizotypal Personality Questionnaire (SPQ), and the Eysenck Personality Questionnaire (EPQ). Scores on the AQ, SPQ, and the "Neuroticism" and "Psychoticism" scores of the EPQ were significantly higher in adults with AS than in controls. The "Extraversion" and "Lie" scores of the EPQ were significantly lower in adults with AS than in controls. The total score of the AQ was correlated with 3 subscale scores (unusual perceptual experiences, odd or eccentric behavior, and suspiciousness) of the SPQ in the AS group, but not in the control group. The findings demonstrated that AQ and other personality scales could be used to elucidate the clinical characteristics of AS in adults. (Contains 2 tables.)