Desoxyhemigossypol 6-O-methyltransferase (dHG 6-OMT) was partially purified from the cotton stele tissue inoculated with Verticillium dahliae by ultracentrifugation, anion exchange chromatography, and gel filtration chromatography on a FPLC column. The enzyme which was purified 267-fold catalyzed the transfer of the methyl group of S-adenosyl-L-methionine (SAM) to the 6-hydroxy group of desoxyhemigossypol (dHG), one of the several sesquiterpenoid phytoalexins induced in response to the fungal attack.