The cell growth rate and cellular lipid content of microalgae are affected by the nitrogen levels during cultivation. The growth rate and lipid content of marine microalga Tetraselmis sp. was found to increase under nitrate replete conditions, but not under deplete conditions. Thus, in order to enhance the lipid productivity of Tetraselmis sp., a two-stage culture process utilizing nitrate replete condition was applied. When the cells were cultivated in F/2 medium for five days in the first stage, the obtained lipid content and productivity were 22.4% and 26.7mgL(-1)d(-1), respectively. After second stage of cultivation for a further 36h under nitrate replete conditions with 8.82mM NaNO3, increased biomass concentration of 1.32gL(-1) and lipid content of 30.5% were obtained, with an enhanced lipid productivity of 47.3mgL(-1)d(-1).