Treatments for cocaine abuse have been disappointingly ineffective, especially in comparison with those for some other abused substances. A new approach, using vaccination to elicit specific antibodies to block the access of cocaine to the brain, has shown considerable promise in animal models, and more recently in human trials. The mechanism of action for the antibody effect on cocaine is very likely to be the straightforward and intuitive result of the binding of the drug in circulation by antibodies, thereby reducing its entry into the central nervous system and thus its pharmacological effects. The effectiveness of such antibodies on drug pharmacodynamics is a function of both the quantitative and the qualitative properties of the antibodies, and this combination will determine the success of the clinical applications of anti-cocaine vaccines in helping addicts discontinue cocaine abuse. This review will discuss these issues and present the current developmental status of cocaine conjugate vaccines.