A simple and inexpensive Pbs-FET with high sensitivity and short response time was developed which consists of a PbS layer on a pH-sensitive gate of a field effect transistor. The PbS-layer was prepared with simple wet precipitations technique. The PbS-FET has about the same selectivities for Pb2+- and for Cu2+-ions, but only slight sensitivity for Cd2+- and Zn2+-ions. The sensor was integrated in a FIA system. By variing the injection time the measuring range varied between 10(-1)-10(-6) and 10(-2)-10(-8) mol Pb2+/1. The PbS-FET-FIA system is suitable for monitoring of Pb2+ concentrations in drinking water.