Leishmaniasis is a neglected disease that affects millions of people worldwide. Poor efficacy and high toxicity of the limited treatment options demonstrate the need for the development of new chemotherapeutic agents to treat this disease. In order to respond this concern, the development of novel Ru-azole complexes as chemotherapeutic agents by inhibiting the cytochrome P-450 dependent C14-&agr;-demethylation of lanosterol to ergosterol which is essential for the parasite survival. In addition, Ruthenium would enhance the activity of the parental drug, by helping ketoconazole/clotrimazole to cross the parasite membrane, together presenting low toxicity. The viability and citotoxicity of the Ru-azole compunds was tested against Leishmania major and different mammalian cells lines. Based on these experiments Ru-azole complexes represent excellent leads for the development of new chemotherapeutic agents to treat leishmaniasis