A sentinel surveillance system of the public health service for acute respiratory diseases (ARD), especially influenza, has been realized in the Free State of Saxony of Germany for 25 years. The epidemiological sentinel is based on weekly registration of morbidity and mathematical-statistical calculations. For a microbiological sentinel, a fast diagnosis by nucleic acid amplification techniques and improvements of sample management in connection with the rapid transmission of results have been introduced. In the present report, the ARD/influenza sentinel is demonstrated for the season 2000/2001. The sentinel system provides scientific and practical information for a prophylactic and therapeutic control program. Economic significance has been proved by verifiable numerical data derived from several epidemiological and microbiological investigations. The realized system has been considered superior to the influenza surveillance scheme of the Arbeitsgemeinschaft Influenza (AGI, Marburg, Germany) for all Germany and another system of a pharmaceutical company which is under construction.