The purpose of our study was to optimize the dextran production in Leuconostoc mesenteroides CS-5, which was isolated from Chonggak kimchi. To measure dextran productivity, rheological analysis and the dinitrosalicylic acid method were applied. For optimization of dextran production, 10-30% sucrose (w/v) was added to MRS medium; the highest viscosity value was found after the addition of 30% sucrose (0.153 Pa·sn), which was much higher than that found in the control (0.01 Pa·sn). However, the production of dextran by L. mesenteroides CS-5 was entirely inhibited by the addition of 17% maltose (w/v) to medium containing 30% sucrose. A subsequent test with skim milk revealed that most vigorous dextran production occurred during cultivation at 22℃ with 1.5% skim milk - 0.30 Pa·sn (compared to 0.22 Pa·sn at 25℃). L. mesenteroides CS-5 is regarded as a facultative psychrophile (cold-loving bacteria). The addition of CaCl2 increased the viscosity of the medium, owing to the production of dextran, by more than two-fold. The optimum concentration of CaCl2 was determined to be 0.01% (w/v) which resulted in a viscosity value of 1.35 Pa·sn. Comparative analysis was performed using dinitrosalicylic acid tests to measure amounts of dextran according to absorbance (O.D.) at 550 nm. The highest dextran production occurred within 48 hr of incubation when using additions of 1.5% skim milk and 0.01% CaCl2 (113.24±0.80 and 112.13±0.2, respectively). In an attempt to enhance dextran production further, the number of cells inoculated into the optimized medium was increased from 109 to 1010 and 1011 cells per 10 ml. As expected, the concentration of dextran was significantly increased by the inoculation of more cells. For 36-hr incubation, values of O.D. produced by inoculation of 1.0×1011 cells reached 123.75±0.25 (30% sucrose), 121.65±0.38 (1.5% skim milk), and 119.80±0.28 (0.01% CaCl2); compared to 55.40±0.44 (30% sucrose), 76.83±0.06 (1.5% skim milk), and 119.80±0.28 (0.01% CaCl2) when 1010 cells were used. During 48-hr incubation, the highest dextran production was achieved with the addition of 1.5% skim milk and 1.0×1011 cells/10 mL (152.07.78), whereas the values resulting from additions of 30% sucrose and 0.01% CaCl2 treatments were 124.33±0.03 and 142.10±0.87, respectively. This implies that those values are the maximum values achievable for dextran production in L. mesenteroides CS-5. Thus, increasing the number of cells inoculated can facilitate optimum dextran production.