Risk perceptions and incentives are two important predictors of individual intention to donate blood, but this requires further explanation due to the problem of inconsistencies that occur in relation to attitudes and behaviors. This study conceptualizes altruism as a moderator that will give a detailed explanation of the problem of inconsistency. It examines the effects of risk perceptions and incentives on positive attitudes and individual intentions in donating blood, moderated by altruism. A sample of 200 individuals was taken randomly at various public places in Surakarta, Indonesia, including malls, hospitals and during a car free day event. The multigroup structural equation model is a statistical tool used to describe the relationship between conceptualized variables. This study provides clarity that altruism is a moderating variable that can explain the intention of individuals in donating blood.