Beta-Galactosidase (beta-gal) and 6-phospho-beta-galactosidase (P-beta-gal) activities were measured in a total of 34 strains from Lactobacillus acidophilus, Lactobacillus crispatus, Lactobacillus amylovorus, Lactobacillus gasseri and Lactobacillus johnsonii. The Lact. gasseri strains have P-beta-gal but little or no beta-gal activities. The strains from other species have beta-gal but only very little P-beta-gal activities.