Researchers have carried out a substantial number of studies on helping behaviors in various disciplines. In the area of organizational behaviors, employees’ helping behaviors have been studies by many researchers. Most of these studies assume that employees will behave in an identical manner toward everyone else. However, in real organizations, employees behave in different manners depending on the partners. The present study investigates the motivational mechanism of employees’ helping behaviors in a dyadic relationship by considering their psychological motives for helping, characteristics of recipients as social exchange partners, and interaction effects between these two factors. To explain motivational mechanism of helping behaviors, the present study is based on the motivational approach. The motivational approach assumes that helping behaviors are induced by self-oriented goals or by other-oriented goals. In particular, this study focuses on the self-oriented motivational mechanism. In the selforiented perspective, people help others with instrumental purposes such as enhancing their self-images or getting helping back from recipients in the future. The specific purposes of this study are like these. (1) I examined the effect of actor’s self-enhancement motives as a selforiented motivational orientation on helping behaviors toward a focal coworker. (2) Coworker’s characteristics which the employee perceives affect helping behaviors toward this coworker. This phenomenon can be explained by self-oriented perspective. This study suggests coworker’s characteristics as determinants of helping behaviors. By the self-oriented perspective, recipient’characteristics which are related to expectation of future rewards- ability, quality of leader-member exchange (LMX), and popularity- might affect helping behaviors. I examined the effects of these three coworker’s characteristics (ability, LMX, &popularity) on help-giving behaviors toward this coworker. (3) previous studies suggest that each motivational orientation drives people to focus their information searching and processing on different kinds of attributes. Based on this argument, the present study proposes the interaction effects between self-oriented motives and recipient’s characteristics which are related to the expectation of future rewards on helping behaviors. Data were collected using questionnaires distributed to employees and their coworkers who were working in large companies located in South Korea. A total of 148 employee-coworker dyads were used for statistical analysis. Help giver’ motives and recipient’ characteristics were rated by actor (help giver). Helping behaviors toward focal coworker were rated by both actor and recipient. These dependent variables rated by two sources are reported in the result. Results of this study provide several important theoretical and practical implications. First, main effect of self-enhancement motives was significant. Second, main effects of recipients’ ability and popularity on helping behaviors were significant. Based on this finding,the current study suggests that receiver’s characteristics have to be considered to understand why employee helps particular coworker in the dyadic coworker relationship. Third, selfenhancement motives moderated the relationship between recipient’s characteristics and helping behaviors. Results of interaction patterns between self-enhancement motives and recipient’s characteristics are more complicated than what the hypothesis expected. Interaction patterns are different depending on recipient’s characteristics even if employee has identical selfenhancement motives. This finding means that people who have self-oriented motives might more complicatedly calculate benefit and loss from helping coworker who has specific characteristics. Findings of the current study provide guidelines to enhance helping behaviors of employees with special motivational orientations by working with coworkers who possess suitable characteristics. Future research needs to investigate other motivational factors of helping behaviors besides individuals’ motivational orientations and recipients’ characteristics that are considered in the present study.