In view of social exchange theories, the present research tested the equity, investment, and reciprocity models of the intimate relationships. One hundred couples in romantic relationships responded to the questionnaire concerning the reward and cost, commitent, social resources, and affective reactions toward relationships. The regression analysis revealed that the reward and cost of the relationships were both positively related to satisfaction and commitment. Social resources such as love, service, and goods were reciprocal within couples. These results are consistent with reciprocity model. The roles of reward and cost in social exchange processes in close relationships are discussed.