We examined the systematic assay of the reporter gene for the assessment of heavy metals and organic chemical pollutants using the reporter plasmids carrying stress-responsive elements fused to the green fluorescence protein (GFP) gene as follows: metallothionein (MTIIA), heme oxigenase-1 (HO-1), quinone reductase (ARE), and c-fos genes. The treatment of COS7 cells in which the c-fos gene promoter-, ARE-, or HO-1 enhancer-fused GFP with a low concentration of NaAsO(2) was introduced led to the detection of the fluorescent cells, and an agrichemical paraquat enhanced the fluorescence of ARE or HO-1 enhancer-transfected cells. The cells in which the plasmid carrying the MT-IIA gene promoter (the -765 bp upstream from the transcription initiation site) was introduced highly expressed GFP on treatment with CdCl(2), ZnSO(4), or CuCl(2). The plasmid carrying seven metal-responsive elements of the MT-IIA gene increased the response of the fluorescence intensity to these heavy metals. These results indicated that the use of the gene promoters and enhancers of the stress-responsive genes fused to GFP contributes to the visualization of pollutant-responsive mammalian cells and can be applied to biomonitoring of environmental pollution.