Genetic screening by hybridization with tet M and let 0 DNA probes demonstrated, in Salmonella strains iso lated in 1996, the following: 14/15 (93.3%) of S. enteritidis strains and 9/ 12 (75%) of S. typhimurium strains harbored the tet M determinant; I 0/15 (66.6%) ofS. enteritidis strains and 7112 (58.3%) of S. typhimurium harbored also the tet 0 determinant. The PCR screening, for which we used primers provided by Dr. Elisabeth Chaslus Dancla, !NRA Tours, France, and which underline a common fragment for the A,B,C,D,E determinants, was negative. The presence of the tel Mand tel 0 determinants, which code the resistance mechanism by ribosomal protection against all types of tetracycline (first generation and the analogues of the second generation) could be attributed to a genetic acq uisition from Gram-positive bacteria. In conjugation tests, with£. coli BM2 l (gyr A, Nair), tetracycline resistance shown high transfer frequency, which suggests the possibility of high epidemiological ri sk. The origin of strains - three Romanian geographical regions - suggests that the M and 0 tetracycline resistance determinants were widespread among avian S. typhimurium and S. enteritidis strains.