In this study, microbial activity enhancement effects of ultrasonic sound waves in kefir fermentation were investigated. For this purpose, the effect of ultrasonication (5 min continuous, 22 mm prob, 24 kHz, 400 W, 30% amplitude) on fermentation time was evaluated in kefir production. The microbiological analysis, pH measurement, titratable acidity (lactic acid %) were performed during the fermentation. The produced EPS was measured at the end of the fermentation. The fermentation time was decreased 1 h by ultrasonication applied in kefir fermentation. Even more, the ultrasonication treatment was improved EPS and lactic acid production rate. However, it did not affect production of EPS and lactic acid in kefir statistically (p > 0.05).