In an extensive host range study of M. hyorhinis mink lung cells (MvlLu, ATCC CCL 64) were found to be the cells of choice for the propagation of this mycoplasm, which otherwise is often difficult to grow in a cell-free medium. Furthermore, rapid plaque assay and plaque purification procedures were developed for M. hyorhinis. The titer of M. hyorhinis grew to 1 X 10(7) to 1 X 10(8) pfu/ml within three d postinoculation on mink lung cells. DNA restriction enzyme analysis of the genome of M. hyorhinis was performed. Endonucleases Bst EII and Xho I are the most suitable enzymes for cleaving M. hyorhinis DNA into distinct fragment patterns. Thus, the use of the combination mink lung cells for mycoplasma growth with subsequent restriction enzyme analysis leads to an unambiguous detection and identification of M. hyorhinis strains even in minute amounts.