The present study investigated the relationship between people's social value orientations and helping behavior. Subjects dassified a priori as either cooperators, individualists, or competitors were mailed a request to volunteer from zero to ten hours of their time to a worthy cause. Subjects were asked to indicate on their response forms the number of hours, if any, that they wished to contribute and to retum these forms using an enclosed self-addressed envelope regardless of whether they intended to donate any hours. The results revealed that subjects of all three social value orientations were equally likely to comply to the small request to return their response forms. However, the number of hours that subjects contributed differed as a function of their social values. As predicted, cooperators contributed significantly more of their time to the cause than did individualists and competitors. We relate these findings to previous research on social values and helping behavior.