Protein synthesis has been a very rich target for developing drugs to control prokaryotic and eukaryotic pathogens. Despite the development of new drug formulations, treating human cutaneous and visceral Leishmaniasis still needs significant improvements due to the considerable side effects and low adherence associated with the current treatment regimen. In this work, we show that the di-substituted urea-derived compounds I-17 and 3m are effective in inhibiting the promastigote growth of different Leishmania species and reducing the macrophage intracellular load of amastigotes of the Leishmania (L.) amazonensis and L. major species, in addition to exhibiting low macrophage cytotoxicity. We also show a potential immunomodulatory effect of I-17 and 3m in infected macrophages, which exhibited increased expression of inducible Nitric Oxide Synthase (NOS2) and production of Nitric Oxide (NO). Our data indicate that I-17, 3m, and their analogs may be helpful in developing new drugs for treating leishmaniasis.