The effects of acute of marine toxicants on early life of coastal olive flounder were investigated. An increasing order of acute toxicity on embryo- and larva-stages of Paralichtys olivaceus was CdCl2<HgCl2<Basta<Aroclor 1254, and the toxicant effect was more severe on the larva-stage than the embryo-stage. The hatching percentage depended upon the concentrations of toxicants exposed at the embryo stage. The fry deformed from hatching at high toxicant concentrations died immediately, and the yolk-consumption rate of just hatched fry was slower at the higher-toxicant concentrations. For Aroclor 1254, Basta, HgCl2 and CdCl2, the values of 72hr-LC50 at embryo-stage were estimated to be 15.5ng/L, 21 nL/L, 17 $mu extrm{g}$/L and 29 $mu extrm{g}$/L, respectively, and those values at larva-stage were estimated 3.5 ng/L, 16.0 nL/L, 10.5 $mu extrm{g}$/L and 15.0 $mu extrm{g}$/L, respectively.