Brucellosis is an urgent infectious disease of livestock and wild animals and the commonest human zoonosis. Diagnosis of brucellosis is rather complicated and it has to be obligatorily confirmed by laboratory testing. Direct bacteriological and molecular methods and indirect serological tests are used for brucellosis diagnostics. The choice of the diagnostic tools depends on the overall epidemiological situation in the region and the objectives of the study: validation of the diagnosis, screening (monitoring), cross-sectional studies or confirmation of brucellosis-free status of the region. The review describes current bacteriological, serological and molecular methods, routinely used for the diagnosis of brucellosis in humans and animals. The perspectives of brucellosis diagnostics are also discussed.