Cysteine proteinases (CPs), a type of important hydrolysis proteases, have played an essential role in plant growth and in response to biotic or abiotic stresses. Based on the available EST sequence, a 1 056 bp cDNA named by HbCP3 was segregated out by using specific primers from root tissues of rubber tree (Hevea brasiliensis Muell. Arg.). The cDNA contained a length of 1 023 bp ORF (open reading frame), 13 bp 5' UTR and 20 bp 3' UTR. Sequence analysis suggested that HbCP3 had a deduced code of 340 amino acids with a theoretical molecular weight (Mw) of 37 350 and with isolectric point (pI) of 5.24, and it belonged to a secretory protein located in vacuoles; The protein, containing one Inhibitor_I29 domain and one Peptidase_C1A domain, could be classified into the papain C1 family; Since the protein shared more than 80% similarity with its homologs Ricinus communis and Populus trichocarpa, it was hence named by HbCP3. Results of the expression analysis showed that among in all tissues, i.e., root, bark, xylem, bud, leaf, petiole and laticifer, HbCP3 only exhibited in root.