We performed a questionnaire study among 413 consecutive voluntary unpaid blood donors being bled for the first time. About 50% were aged below 26 years, 93% were employed or students, and 50% of the donors came from families with other blood donors. The motives to donate blood were investigated. As motives we found: altruistic and humanitarian reasons in about 98%, to obtain a greater well-being in about 60%, tradition at the place of employment or in the family about 35% each. The importance of blood tests taken in connection with the blood letting was analysed. We could not find any support for the hypothesis that blood donors in Denmark enroll as donors to be tested for HIV antibodies.