Beauveria bassiana protoplast formation from blastospores, conidia and mycelia was studied. The method of protoplast formation involves preincubation of the fungal cells with dithiothreitol and subsequent treatment with an enzyme mixture consisting of: cellulase, chitinase, β-glucuronidase and lysozyme. Using this procedure protoplasts were formed from blastospores and mycelia but not conidia. Formation of protoplasts from 24 hour old mycelia was 100% efficient using the above conditions. A number of ionic and osmotic protoplast stabilizing agents were tested. Ammonium sulfate was shown to be the stabilizer of choice. Protoplasts were stable when stored at 4° C with a loss of only 17% in 6 days. We suggest that this procedure of protoplast production will allow a gentler method for the extraction and isolation of intact high molecular weight DNA from B. bassiana.