This study attempts to examine the common factors between firms’ efforts to perform ‘corporate social responsibility (CSR)’ activities (especially activities for the benefits of their employees)and ‘high performance work systems’ through the case of the Mondragon Corporation Cooperatives. Firms can be regarded as one of the social formation and thus they have to perform duties which are assigned to the firm. Firms can survive with the help of other members in the society. Therefore, firms have to conduct the ethical and socially desirable behaviors which have positive effects on other members of the society. This study shows the CSR activities conducted by the Mondragon Corporacion Cooperativa. Employees at the Mondragon usually show high level of morale and satisfaction toward their firm based on the CSR activities performed by their firm because the firm assures the employment security, gives employees opportunities to take part in the decision-making process, and performs some other HR practices which have positive effects on employee attitudes and behaviors. These HR practices can be considered as the part of the high performance work systems. Accordingly, this study attempts to show the concomitant features between corporate social responsibility activities and high performance work systems and argues that firms can increase the level of the efficiency in managing their human resources when they perform the corporate social responsibility activities.