Various culture conditions for the production of fermented whey presenting bifidogenic growth stimulator (BGS) activity were evaluated using Leuconostoc mesenteroides CJNU 0147 and Lactobacillus casei CJNU 0588. The BGS activity of fermented whey produced with mixed culture of Leu. mesenteroides CJNU 0147 and L. casei CJNU 0588 was higher than those of single cultures. The optimal temperature for the production of the fermented whey was $20^{circ}C$. The anaerobic culture conditions via nitrogen gas supply had no influence on the BGS activity of fermented whey. The BGS activity of the heat-treated fermented whey samples was slightly decreased by 7.63, 11.66, and 15.12% at 80, 100, and $121^{circ}C$, respectively for 15 min. Pilot-scale (75 L) fermented whey was produced using the 2 freeze-dried cell powders of CJNU 0147 and CJNU 0588 and spray-dried. The spray-dried fermented whey presented BGS activity, indicating it can be used as a functional food material.