Recent studies based on J. Bowlby's (1969/1982) attachment theory reveal that both dispositional and experimentally enhanced attachment security facilitate cognitive openness and empathy, strengthen self-transcendent values, and foster tolerance of out-group members. Moreover, dispositional attachment security is associated with volunteering to help others in everyday life and to unselfish motives for volunteering. The present article reports 5 experiments, replicated in 2 countries (Israel and the United States), testing the hypothesis that increases in security (accomplished through both implicit and explicit priming techniques) foster compassion and altruistic behavior. The hypothesized effects were consistently obtained, and various alternative explanations were explored and ruled out. Dispositional attachment-related anxiety and avoidance adversely influenced compassion, personal distress, and altruistic behavior in theoretically predictable ways. As expected, attachment security provides a foundation for care-oriented feelings and caregiving behaviors, whereas various forms of insecurity suppress or interfere with compassionate caregiving. ((c) 2005 APA, all rights reserved).