Objective: To describe The Prosocial Personality (PSP) and its dimensions in Voluntary Blood Donors, the motivating (F+) and the hampering factors (F-). To relate PSP to F+ and F-. Methods: Study design: Cross-sectional descriptive study. Setting: Tucuman, Argentina. Respondents: Voluntary blood donors of both sexes over 18 years old. Interventions: The Prosocial Personality Battery was used to assess the following variables: Age, Sex, Degree of PSP, F+, F- and Previous Donations. Main outcome measures: Degree of PSP, and F+ and F- frequency. Results: n=37. 29 respondents presented a moderate degree of PSP whereas 8 presented a high degree. There was no correlation between the PSP dimensions. 22 of the donors was motivated to “help children”, 19 to “achieve the personal satisfaction of helping others”, and 17 to “be helpful for society”. As regards the factor which would influence the population most when considering blood donation, 17 explained that it would be “the fear of not feeling well”, 16 mentioned “the lack of knowledge about donation centers”, and 14 referred to “being afraid of the needle prick”. There is no association between the PSP and the F+ and F-. Conclusions: It could be inferred that there is something which prevents empathic thoughts and feelings form becoming concrete actions. It is of paramount importance to establish what this element is in future research, since its identification and eradication would promote the realization of the above-mentioned thoughts and feelings into prosocial actions, such as voluntary blood donation.