We have cloned a chitinase cDNA (MpChi-1) from plantain (Musa paradisiacal L) using rapid amplification of cDNA ends (RACE) according to a sequence fragment which we had cloned using the suppression subtractive hybridization (SSH) technique. The MpChi-1 encodes a protein of 326 amino acids and belongs to acidic chitinase class Ib subfamily. MpChi-1 shares high identity with rice endochitinase (XP_468714) and different each other only at three residues. Homology modelling indicated these three substitutions would not change the configuration of the activity site of the enzyme. We have expressed recombinant MpChi-1 and purified by ammonium sulphate precipitation and preparative reversed phase HPLC. The recombinant protein could hydrolyse chitin and inhibit the growth of the Gloeosporium musarum Cke and Massee in vitro. Northern blot revealed that the MpChi-1 transcripts rapidly after inoculation with G. musarum and maximum mRNA accumulation reached at 48 h. Jasmonic acid (JA) and salicylic acid (SA) could induce MpChi-1 expression, while mechanical wounding, silver nitrate and osmotic stress stimulated only a slight accumulation of MpChi-1 transcripts. Abscisic acid (ABA) could induce MpChi-1 transcript. These results suggest the MpChi-1 plays important role in the events of the hypersensitive reaction (HR).