Pau-brasil is a tree belonging to the Leguminosae family (Cesalpinoidea sub family). Aminopeptidases are enzymes that participate in the final stages of protein degradation and hydrolyze peptide bonds yielding amino acids from N-terminal peptides and act on some artificial substrates like aminoacyl-2-naphthylamides (AA-NA). The aim of this work is to study aminopeptidases from C. echinata seeds. The seeds were ground, and its proteins were extracted in 0.15M NaCl and fractioned  by acetone  and the dried pellet dissolved in 0.1 M ammonium acetate buffer, pH 8.3 / 0.03 M NaCl. The proteins were purified by ion exchange chromatography (Resource Q) in FPLC, equilibrated and washed with 20 mM ammonium acetate buffer, pH 8.5 and eluted with a linear gradient of 0.5 M NaCl (0 to 100%) in the same buffer. The protein from peak 5 showed the most aminopeptidase activity upon Ala-, Leu- and Arg-NA, as substrates. The pool fractions of peak 5 were submitted to DEAE Cellulose Cellex D column equilibrated and washed with 0.02 M NaPB, pH 7.0. Elution with a linear gradient of 0.02 M to 0.3 M NaPB, pH 7.0 provided two protein peaks with activity on AA-NA, P₁ and P₂. The effluent, eluted at 1,3 mS (P₁), was submitted to Octyl Sepharose Fast Flow column, equilibrated with 0.02m NaPB / 3M KCl. Elution with a linear gradient of KCl (3.0 to 0 M) in 0.02M NaPB, pH 7.0, followed by water and i-propanol 30%, provided one protein peak (P₁a) in 12 mS. Pool P₂ was submitted to the same hydrophobic chromatography, in the same conditions and it was eluted only one active protein peak (P₂a) in 14 mS. The pool P₁a was lyophilized and filtered on a Superdex 75 column, equilibrated and developed with PBS. Two protein peaks P₁a₁ and P₁a₂ with enzyme activity were obtained. It doesn’t know the real importance of aminopeptidases from C.echinata seeds, but as aminopeptidases from Phaseolus vulgaris and Zea mays seeds, the aminopeptidases of Caesalpinia echinata coud be involved in the seed germination.