With the new method the fecal flora of 13 clinically healthy dogs aged 3 to 42 months was analysed qualitatively and quantitatively. It was characterized by that bacteroidaceae constituted the most prodominant flora, catenabacteria, streptococci, peptostreptococci, lactobacilli and bifidobacteria were the next most numerous, enterobacteria consisted the accompanying flora. The numbers of Clostridium perfringens were remarkably fluctuated and seem to be influenced by the composition of the food ingested by the host. The total cultivable counts averaged log 10.8 +/- 0.2/g. The composition of the Lactobacillus flora and Bifidobacterium flora in the feces of 34 dogs from 3 different age groups was analysed. In the feces of all age groups L. acidophilus, L. salivarius and L. fermenti with 9 different types were found. Within the lactobacilli L. acidophilus type VI c, L. salivarius type VI a and L. fermenti type IV b were most frequently found. L. acidophilus types VI c and XI, L. salivarius types VI a and VI b could not be placed in any established types of each species, and were described as new types. Bifidobacteria were regularly found in large numbers in the feces of dogs aged 2 to 24 months. B. adolescentis and B. pseudolongum consisted the main Bifidobacterium flora.