Morphological, cultural and physiological properties of two strains of soil thermophilic actinomycetes were studied. These strains were compared to the actinomycetes of related genera and were found to be close to Micropolyspora and Actinomadura. However, they differed from both genera by the structure of the sporiferous apparatus, from Micropolyspora by the type of the cell wall, and from Actinomadura by the fatty acid composition of lipids of the mycelium. A new genus of actinomycetes, Excellospora Agre a. Guzeva gen. nov., is suggested on the basis of this study. Two species belonging to the genus Micropolyspora are proposed to assign to the new genus as Excellospora viridinigra and Excellospora rubrobrunea. Since these strains differ from the aforementioned species by the traits used for differentiation of the species of actinomycetes, they are described as a new species of the new genus Excellospora Agre a. Guzeva gen. nov. sp. nov.