The estimation of the frequency isolation of streptococcus in birds, farm and domestic animals and study of their specific characteristics during the years 2004–2011 is given. The frequency of isolation streptococcus in birds was 84,1 %, in animals – 34,1 %. Among animals the highest isolation of streptococcus was belonging to the group of «other» (dogs, cats, rabbits, seals) – 71,3 %, the lowest – at examination of cattle – 23,6 %. The etiological structure of streptococcosis was quite various and represented six species of microorganisms (E. faecalis, E .faecium, Е. durans, S. pneumoniae, S. pyogenes, S. cremoris). E. faecalis were the main microorganisms in Baikal region. E. faecalis dominated in the etiology of streptococcosis at animals (79,5 %) and birds (92,9 %). S. pneumoniae have considerable importance in pigs and small cattle (besides E. faecalis). Streptococcus E. durans was isolated in birds only.