--The progressive increase in resistance to current control approaches developed by Leishmania raises the need to develop therapeutic strategies based on the comprehensive knowledge of the biology of the parasite. The enzyme Nicotinamide Mononucleotide Adenylyltransferase (NMNAT, EC 2.7.7.1) catalyzes the central step in the biosynthesis of the nicotinamide adenine dinucleotide (NAD+), making it essential for the survival of all organisms. NAD+ metabolism is related with the maintenance of several biochemical, cellular, and physiological processes. Consequently, characterization and analysis of the enzymes involved in its biosynthesis represents a key point in the development of control strategies. In this study, the NMNAT enzyme of different species of Leishmania was identified through bioinformatics procedures. The sequences found were used in the construction of structural homology models, which revealed characteristic elements common to NMNATs. The open reading frame of the NMNAT of L. braziliensis was cloned from complementary DNA, and the enzymatic activity of the corresponding recombinant protein was confirmed through enzymatic assays. Primary structure analysis showed a Leishmania ¿ specific amino terminal insertion of the parasite NMNATs. The deletion of this insertion is negatively correlated with the enzymatic activity in vitro. Based on our observations, we suggest the amino terminal insertion of Leishmania NMNATs as a promising pharmacological target for development of specific control strategies.