Аннотация:This chapter presents an overview of a flow injection thin-layer cell immunosensor with chemiluminescent detection of peroxidase label. A new type of flow injection enzyme immunosensor for detection of analytes in kinetic and steady-state regimes based on competitive scheme of analysis, flow ultranarrow plane polystyrene cell and peroxidase labeled antigens was developed. The very sensitive enhanced chemiluminescence system was used to detect the peroxidase label in enzyme immunoassay. The flow cell with specific antibodies immobilized on its walls was placed directly into a cell compartment of luminometer, just in front of photomultiplier tube for immediate registration of the label quantity under passing of substrate solution through the cell. The analysis was realized in a continuous cycle mode by passing the solutions of analyte, labeled antigens, washing buffer and substrates through the cell. The cell was used for many times after regeneration of the surface by acid solution and subsequent absorbtion of specific antibodies. The overall time for one cycle was about 10 min.