Millions of people worldwide are infected by some kind of parasite and millions are in risk of contracting infection. In addition, it is now accepted that parasites are rapidly developing resistance to drugs that a few years ago were effective. This gloom picture underscores the urgent need to develop new drugs against parasitic diseases. Fortunately, the important technological advances that have been made in the past years will, in principle, facilitate the discovery of new and effective agents against parasitic diseases. In many of the approaches for drug design the basic premise is the identification of a macromolecule that is central to the life of the parasite. Because the life of all living organisms depends on multiple protein-protein interactions and the function of oligomeric proteins, it is worthwhile to explore if protein interfaces could be exploited for drug design. Here we review some of the work that has been done in this direction, and attempt to call attention to the richness of protein-protein interfaces for the design of agents that could lead to the development of drugs against parasitic diseases.