A discrepancy exists between the demand for and the availability of solid organs for transplant. Barriers to organ donation can be encountered at 2 key points: (1) when trying to increase the number of people willing to become organ donors and registering their intent and (2) at the time of organ procurement. Several predictors of individual willingness to register as an organ donor are discussed, along with issues surrounding families' refusal of consent or failures in the hospital system to identify potential donors. Several countries have adopted presumed-consent policies and have seen a subsequent increase in donation rates. Research is needed to explore the effectiveness of approaches to overcome the barriers to individual registration and family consent, particularly in countries where presumed consent has not been and is not likely to be adopted.