[en] On the basis of the Chernobyl experience the Czechoslovak government decided in July 1986 to set up Czechoslovak Monitoring Network and to assign the Centre of Radiation Hygiene of the Institute of Hygiene and Epidemiology to be its headquarters (Centre of Czechoslovak Monitoring Network). The requirements for emergency monitoring are stated in the document The principles of Monitoring for Protection of Public Health in case of a Radiation Accident approved by the Czechoslovak government in April 1987. Assignments of components of the Network, equipment and technical support required, aims of their activities and chronological order of their activation are stated in the document Requirements on Monitoring, Setting up and Equipment of the Czechoslovak Monitoring Network drawn up by the Centre and approved by the Czechoslovak Governmental Commission for Coordination of the Measures in Case of a Radiation Accident in April 1988. It should be noted, however, that basic principles of environmental monitoring aimed at obtaining the complete information of radiation situation, discharges and releases of radionuclides both during the normal operation and in case of an accident were worked on since putting the first PWR-type NPP in Czechoslovakia into operation in 1979. In March 1986 the Instruction for emergency monitoring was approved by the commission. The existence of this instruction and corresponding professional, technical and organizational preparedness of organizations departments responsible for monitoring manifested its positive impact especially in the situation after the Chernobyl accident. This fact refers especially to institutions of hygienic service and nuclear power engineering. National and international experience gained after the Chernobyl accident led to some elaboration in the organization of monitoring and to more precise definition of its conception