Twenty-six strains of N. dassonvillei (Brocq-Rousseu) Liegard and Landrieu from the soil and from infections of man and animals are described and a pattern of characteristics for their identification and differentiation from N. asterotdes, N. brasiliensis, N. caviae, N. madurae and N. pelletieri presented. Strains of N. dassonvillei resembled strains of S. griseus (Krainsky) Waksman and Henrici in the macroscopic appearance of their growth and in many of the physiological properties examined.