The solubility of a modified recombinant Bacillus licheniformis R-amylase (mBLA) has been studied by batch crystallization. A semi-pure preparation was chosen containing five isoforms with pI values from 6 to 7.3 (weighted average of 6.6). Small amounts (<1 %) of protein impurities were also present. Solubility was studied in the pH range of 6 to 8. The lowest solubility without added salts was 60 mg‚mL -1 at pH 7. The addition of 0.1 mol‚L -1 sodium salts of nitrate, sulfate, and thiocyanate had a small effect on solubility. However, solubility was lowered significantly by adding 0.5 mol‚L -1 sodium sulfate at all pH values and increased with 0.5 mol‚L -1 sodium thiocyanate at pH 7 and pH 8. The effect of anions on R-amylase solubility followed the Hofmeister series, and only weak evidence of reversal was seen below the isoelectric point. Cations had little effect on solubility. The sign and magnitude of the R-amylase potential was determined in the presence and absence of 0.1 mol‚L -1 salt. Qualitatively, potential correctly predicted the different salts influence on mBLA solubility.