Mortierella alpina, an oleaginous zygomycete is a potent producer of arachidonic acid, the pharmaceutically and nutraceutically important polyunsaturated fatty acid of the n-6 series. It serves a wide variety of purposes, from being a purely structural element in phospholipids to being involved in signal transduction, and as a substrate for a host of derivatives involved in second messenger function. Arachidonic acid has applications in diverse areas including infant and geriatric nutrition. In the present study, the interactive effects of four major media constituents on arachidonic acid production were investigated by applying a central composite rotatable design (CCRD) and response surface methodology (RSM). The independent variables, which were selected by concentrations of glucose, corn solids, $KH_2PO_4$, and $KNO_3$ influenced the production of biomass, total lipid, and arachidonic acid by M. alpina. A second-order polynomial was fitted by multiple regression analysis of the experimental data. The optimum conditions (glucose 10.0 g/L, corn solids 5.0 g/L, $KH_2PO_4$ 1.0 g/L, and $KNO_3$ 1.0 g/L) resulted in maximum production of arachidonic acid (1.39 g/L) and the corresponding biomass and total lipid concentrations were 12.49 and 5.87 g/L, respectively.