Optimization of medium components for enhancement of ${eta}$-carotene production by Blakeslea trispora was achieved using mathematical statistics. Optimum concentrations of components using Plackett-Burman design and response surface methodology (RSM) were D-glucose 7.16%, wheat bran extract 4.08%, $MgSO_4$ 0.04%, soybean oil 3%, thiamine 0.01%, soybean meal 1%, and $KH_2PO_4$ 0.2%. Maximum production of ${eta}$-carotene using optimized medium was 643 mg/L in a shake flask. A predicted value of 669 mg/L was based on results of an RSM regression. The optimum aeration rate of 1.5 vvm produced 866 mg/L and the optimum agitation speed of 100 rpm produced 975 mg/L of ${eta}$-carotene. The t of a quadratic model using regression derived coefficients was significant. Maximum production of ${eta}$-carotene using the optimized medium in a stirred tank reactor (10 L) at an optimal aeration rate and an optimum agitation speed with addition of 0.1%(v/v) ${eta}$-ionone was 1,357 mg/L.