The main hazard for forestry workers pose microorganisms which are transmitted by ticks and cause zoonotic diseases: tick-borne encephalitis, Lyme borreliosis, granulocytic anaplasmosis and babesiosis. The remaining occupational biohazards are microorganisms causing other zoonoses (mostly also transmitted occasionally by ticks), fungi causing mycoses and allergic diseases, plant allergens and animal allergens. Totally, 22 agents (or groups of agents) were characterized which pose an occupational hazard for forestry workers. The prophylactic measures comprise the use of protective clothing and repellents, quick and reliable removal of ticks from body surface, vaccination against occupational viral diseases, medical care on forestry workers and health education.