The Zashtita union is holding a protest in Sofia tonight over frozen pay in a large share of hospitals, organisers said. It will take place outside the Council of Ministers and the Health Ministry.
The union says pay has stayed the same in many hospitals, even though there is extra money for healthcare.
Protesters are also unhappy about rising prices, inflation and problems in the health system.
They also object to changes in healthcare that were not discussed with the union. They say changes made without agreement risk destabilising the system.