Aromatic diamidines and related compounds are DNA minor groove binders that have been screened against a variety of pathogenic microorganisms such as bacteria, fungi and protozoa and show promising results. Parasitic infections are widespread in developing countries and are major contributors to human mortality and morbidity, causing considerable economic hardship. Trypanosomes are unicellular protozoan organisms that cause serious public health problems in developing countries: African trypanosomiasis (sleeping sickness) in Africa, and Chagas' disease, in Latin America. Sleeping sickness, caused by sub-species of Trypanosome brucei (T. brucei gambiense and T. brucei rhodesiense), is a fatal disease if left untreated, with about 60 million people currently at risk. Trypanosoma cruzi is the etiological agent of Chagas' disease, an important parasitic illness that affects nearly 17 million individuals in endemic areas. The fact that the available clinical drugs are expensive, toxic, require long treatment periods, frequently exhibit reduced activity towards certain parasite strains and evolutive stages, and are beginning to show development of resistance, demonstrates the urgent need for the development of new drugs for both pathologies. For some time much attention has been focused on the effect of diamidines (and related compounds) on African trypanosomes. However more recent studies have pointed to their potential activity against T.cruzi. In this review the current therapeutic state of the art of aromatic diamidines and related compounds used against T.brucei and T.cruzi is reviewed with a focus on their potential use as antiparasitic drugs for the treatment of both these important neglected diseases.