OBJECTIVE: To conduct a systematic review of published research that assessed the predictors of attitudes toward deceased organ donation, willingness to donate, and donor behavior. DATA SOURCES: MEDLINE, PreMEDLINE, PsycInfo, and the Cumulative Index to Nursing and Allied Health Literature were searched for the period from 1988 to 2009. STUDY SELECTION: Eligible studies included members of the general public (i.e., not transplant recipients, donor families, or health professionals) and used multivariate analyses for quantitative assessment of predictors. Data Extraction-The search identified 33 relevant studies. Owing to heterogeneity in populations and measures, results were summarized rather than subjected to meta-analysis. DATA SYNTHESIS: Research suggests that individuals who are younger, female, have higher education levels and socioeconomic status, hold fewer religious beliefs, have high knowledge levels, know others with positive attitudes, are more altruistic, and have fewer concerns about manipulation of the body of the deceased donor are more likely to have positive attitudes toward donation and are more willing to donate their organs. CONCLUSIONS: The review revealed the complexity of individuals' attitudes toward donation and the need for more sophisticated future studies of the interactions between the broader factors influencing donation (such as social norms and existing legislation in each country) and individual factors, such as attitudes and beliefs. (Progress in Transplantation.