The aim of this study was to produce an autogenous vaccine from Yersinia ruckeri isolate and to test it’s efficacy in field conditions. Colonies of Yersinia ruckeri biotype I isolated from rainbow trout with haemorrhagic septicemia were cultivated in TSB and inactivated with formalin. The vaccine was diluted and administered by immersion of rainbow trout fry (~ 4.5 g BW) in the vicinal suspension. The experimental infection was done 28 days post vaccination by immersing the fry in infectious suspension of the same isolate. Mortality of the control and vaccinated fish was 87% and 11%, respectively. Vaccinated fish showed high level of gained specific resistance to the infection (RPS 87,4%).