Utilizing a four-liter fermentor and applying a complete factorial design 2(3), the combined effects of agitation speed, aeration rate, and corn steep liquor concentration on zeaxanthin production by Flavobacterium sp. were studied. Maximum growth and production of total carotenoids and zeaxanthin were obtained at 600 rpm, 2 vvm and 4.6% corn steep liquor. Under these conditions, zeaxanthin represented 86% of the total carotenoids produced. Lower values of the variables studied resulted in lower growth, volumetric production of zeaxanthin and total carotenoids, and favored the formation of other carotenoids such as beta -carotene and canthaxanthin. The positive effects on growth and total carotenoids and zeaxanthin formation were in a large extent due to the interaction of agitation/corn steep liquor. However, aeration also had a positive effect on growth.