Acute aquatic toxicity of effluents discharged from five dyeing plants in Gyeong-gi province were evaluated to assess whether the current Korean water quality standards(KWQS) could protect aquatic life. Chemical analyses of all parameters regulated under KWQS, except for E-coli, were also carried out to determine regulation compliance of the samples. All the effluent samples were satisfied with KWQS except for the color in only one sample. In acute Daphnia magna toxicity tests, significant mortality was observed in one of five samples and EC50 was 12.1%(95% confidence interval 9.1-16.2), which was in compliance with KWQS. The result of the Microtox assay indicated that acute microbial toxicity existed in effluents from three out of five plants, two of which were in compliance with KWQS. The agreement between regulation compliance of chemical concentrations of effluent and observed toxicity from various biological toxicity tests was very poor to fair (kappa = 0.194~0.250). The data presented suggest that exposure to dyeing wastewater which were in compliance with Korean water quality standards may not be safe to aquatic biota, and multiple tropical levels should be considered in aquatic toxicity monitoring of dyeing industry.