184 urethral swabs from patients with unspecific urethritis were taken. Ureaplasma urealyticum was isolated with 86 (46.74%), and mycoplasma hominis with 26 (14.13%) patients. In the control group of 156 examinees u. urealyticum was isolated in 43 (27.56%), and m. hominis in 13 (8.33%) cases. U. urealyticum with patients was isolated in a significantly larger number than with the control group (p less than 0.05) which shows possible part of this mycoplasma in the etiology of unspecific urethritis.