Strangles is the most important and geographically most widespread bacterial disease of equines in the world, which is caused by the bacterium Streptococcus equi subsp. equi. It is an acute disease manifested by fever, upper respiratory tract inflammation and inflammation of regional lymph nodes. It is transmitted by direct or indirect contact, but a particular threat is posed by subclinical carriers. The most affected group are foals, but adult horses can be infected too. Diagnostic methods include bacteriological, serological and molecular methods. Treatment depends on the stage of the disease and includes supportive therapy and antibiotics if there are indications for their use. The key of control and prevention is implementation of adequate biosecurity measures and indispensable education of horse owners. Since there is no data about seroprevalence of strangles in Croatia, this study was conducted in order to get a clearer picture on strangles in the country. Two hundred ninety one (291) horse sera from eight counties were tested by an indirect ELISA. Results showed that 48 out of 291 were positive (16,5%). Seroprevalence in counties varies from 7,1% to 12,6% with one exception of Sisačko-moslavačka county in which there were 29,6% positive horses. This is explained by the fact that one quarter of Croatian horses live there and most of the year they are in contact with each other. It is evident that the disease is widespread. In order to determine circulating strains and clinical forms of the disease further studies need to be conducted.