Twenty yeast cultures were screened for their abilities to form B- galactosidase enzyme on yeast nitrogen base-lactose and salted whey media. Kluyveromyces lactis, NRRL 1118 produced the highest enzyme level in salted whey medium containing 10% sodium chloride. Physiological studies on K. Lactis NRRL 1118 have revealed that galactose and lactose sugars could support the synthesis of the highest levels of B-galactosidases in the cells of this organism when used as sole carbon sources in synthetic media. These results indicated that the enzyme in K. lactis is of the inducible type. Yeast extract, urea and casein hydrolysate lead to enhanced biosynthesis of the enzyme. The highest enzyme level was produced using salted whey medium containing 10% sodium chloride concentration with an initial pH 4-5 and inoculum size ranging between 4-8% [V/V] depending upon the incubation period. Results obtained were discussed in the light of possible production of the enzyme on salted whey, which is a by-product of dairy industry in Egypt