Chitinases　are　listed　as　one　class　of　pathogenesis-related　proteins,　and　they　have　become　a　popular　research　topic　because　of　their　resistance　to　plant-pathogenic　diseases.　A　chitinase　with　antifungal　activity　was　isolated　from　the　Canadian　cranberry　beans　(Phaseolus　vulgaris).　The　procedure　included　extraction,　ammonium　sulfate　precipitation,　affinity　chromatography　on　Affi-gel　blue　gel,　CM-Sephadex　C-50,　and　Sephadex　G-75.　There　was　an　almost　108-fold　increase　in　specific　activity　of　the　purified　chitinase　compared　with　that　of　the　crude　extract.　The　enzyme　exhibited　a　molecular　mass　of　30.6　kDa　in　sodium　dodecyl　sulfate-polyacrylamide　gel　electrophoresis　both　under　reducing　and　non-reducing　conditions,　indicating　that　it　was　a　monomeric　protein.　The　pI　was　determined　to　be　7.6　by　isoelectric-focusing　electrophoresis.　The　optimum　pH　and　the　optimum　temperature　for　activity　towards　N-acetyl-glucosamine　was　5.4　and　40-55A　degrees　C,　respectively.　It　exerted　a　potent　inhibitory　action　toward　fungal　species　including　Botrytis　cinerea,　Physalospora　piricola,　Fusarium　oxysporum,　and　Pythium　aphanidermatum.　The　chitinase　was　thermostable　up　to　58A　degrees　C　in　both　enzymatic　reaction　and　antifungal　activity.　The　present　findings　demonstrated　a　thermostable　chitinase　from　cranberry　beans　with　potentially　exploitable　significance.