We report here a live cells-based sensorchip fabricated in microfluidic channels in which several laminar flows were achieved. In addition, we established a cytotoxic sensor cell line, which was transfected with a green fluorescence protein (GFP) plasmid derived from the heat shock protein 70B' (HSP70B') promoter, which is induced by cytotoxic reagents [1-4] (Fig. 1,2). The fluorescence in the sensor cells increased in a CdCl2 dose-dependent manner in the microfluidic channels (Fig.3) . In this system, cytotoxic reagents can be quantitatively detected in a quick, sensitive and high- throughput manner. The combination of sensor cells and microfluidic systems will provide an important basis for the development of micro-total analysis systems (μ-TAS) technology, and can be applied to toxicology, environmental assessment and drug screening.