Abstract: The purpose of this study was to study the influence of process parameters on the Lactic Acid Fermentation by Lactobacillus rhamnosus in laboratory scale fermenter. The experiment was designed by Taguchi Method using STATISTICA software. Three parameters have been chosen as the main parameters that affect significantly to the growth of L. rhamnosus; the agitation speed of the impeller, dissolve oxygen level (pO₂) and pH. The most influence and important parameter for the fermentation process is pH at acidic value of 6, followed by stirrer speed (rpm) and pO₂ even pO₂ supplied and rpm played similar function in maintaining suitable dissolved oxygen to the cells.