The objective of this study was to identify as many as possible the proteins expressed in the promastigote stage of Leishmania donovani (HU3 strain). For this purpose, after processing the protein extracts (see next section), the resulting peptides were analysed by reverse phase-liquid chromatography (RP-LC)-MS/MS (Dynamic Exclusion Mode). Mass spectra were searched by PEAKS Studio XPro search engine (Bioinformatics Solutions Inc., Waterloo, Ontario, Canada).