Restriction digestion fragments of DNAs extracted from 14 representative strains of Saccharomonospora azurea, ''Saccharomonospora caesia,'' Saccharomonospora cyanea, Saccharomonospora glauca, and Saccharomonospora viridis and six ''Saccharomonospora''-like isolates were separated by electrophoresis, Southern blotted onto nylon membranes, and hybridized by using two rRNA gene probes cloned from Streptomyces griseus subsp. griseus KCTC 9080, The following four restriction endonucleases were used: BamHI, SalI, PvuII, and XhoI. The resultant five ribotype patterns were considered species specific. The genomic diversity revealed by ribotyping indicates that this method can be used to both characterize and identify saccharomonosporae. All of the test strains contained DNA with three rRNA gene clusters.