Debate continues about whether monetary payments encourage or discourage self-motivated behaviour such as blood donation. With the growing number of paid plasma donation centres in the United States, and the ongoing challenge to recruit and retain volunteer blood donors, a better understanding of the impact of compensation on donation preferences is essential. A sample of 459 undergraduate students (73·9% female, mean age =18·9, SD=1·3years) completed an anonymous online survey that included a question about their preference for donating blood, donating plasma or neither. Preferences were re-assessed after providing information regarding current differential compensation for blood and plasma donations, and in the context of a hypothetical scenario where both blood and plasma donors could receive payment. Participants initially expressed a clear preference for donating blood (73·7%) relative to plasma (3·9%), but these preferences shifted in favour of plasma donation (47·7%) versus blood donation (39·4%) after learning that plasma donors can be paid. However, when asked to consider a hypothetical future wherein payment was offered for either type of donation, participants again reported a strong preference for donating blood (79·3%) relative to plasma (6·3%). These preferences did not differ as a function of sex or donation history. These results suggest that a significant proportion of young adults are positively motivated to donate blood or blood products by the opportunity for payment.