The document describes a field study to investigate the relationship between altruism and blood donating behavior among members of a large midwestern college community. Altruistic behavior is interpreted as combining three motivations: (1) reward-cost, also referred to in terms of behavior as social exchange; (2) social responsibility and reciprocity; and (3) good moods and feelings. Review of social science literature indicates most investigations of altruistic behavior have dealt with emergency-type situations. Intended as a supplement to these investigations, the paper measures the behavioral manifestations of altruism through prosocial behavior in a blood donating situation. Volunteer blood donors were directed to respond to an eight item questionnaire concerning age, sex, race, year in school, socioeconomic status, religion, reasons for volunteering, and feelings after donating. The first six variables were cross tabulated with reasons and feelings, statistically analyzed, and compared with the total college community. Findings indicated that 70% of blood donors were motivated out of a sense of social responsibility. About 10% apparently contributed out of a sense of obligation, with the remaining 20% donating blood for a variety of reasons. Female and white students were significantly overrepresented as donors. Tables, the questionnaire, and references are presented in the appendix. (Author/DB)