One of the most widely believed axioms of management is that a happy worker is a productive worker. However, most research on the nature of relationships between job satisfaction and job performance has not yielded convincing evidence that such a relationship exists to the degree most managers believe. One reason for this might lie in the way in which job performance is measured. Numerous studies have reported that using Organizational Citizenship Behavior to supplant more traditional measures of job performance may result in more robust relationship between job satisfaction and job performance. Although citizenship behavior has been regarded as an important factor and done as a daily work in Japanese company, little research has focused on it. In this study 71 employees who work for the Japanese company were interviewed and found that the most employees engaged in the citizenship behavior for their selfinterests. And then a questionnaire survey was conducted with 403 subjects who provided self-report answers designed to examine the relationship between citizenship behavior and satisfaction, commitment, and stress. In addition the relationship between citizenship behavior and employees' awareness of evaluation was examined. Results showed support for the relative importance of employees' awareness of evaluation as well as satisfaction. Implications for research on the causes of citizenship are discussed.