The paper deals with real-time Multi-Sensor Weigh–In-Motion System (MS-WIM). This system was designed in Poland in a period of 3 years from 2003 to 2006. The embodied system is equipped with 16 piezoelectric load sensors, in the form of narrow 4m long strips, provided by Measurement Specialties. The paper outlines the system structure and its elements ie the weighing site, the data acquisition system and data processing software. Experimental tests indicate that the designed MS-WIM system falls in accuracy class B+(7) in the speed range from 30km/h to 80 km/h.