Lung samples with peumonic lesions and lymph nodes were collected from cattle and sheep and examined for mycopiasma. All the isolates recovered from cattle were identified as Mycoplasma bovirhinis (14.13%). Mycoplasma ovipneumoniae could be detected in 12.9% of sheep lungs, while, 4 isolates (6.45%) from lung samples and 7 (11.29%) from lymph nodes were identified as M.arginini. The efficacy of some antimicrobial agents were tested in vitro against the isolates by the metabolic inhibition test. Enrofloxacin had the highest minimal inhibitory concentration (M.I.C.) values (0.003-0.048) ug/m1). Mycoplasma bovirhinis and M.arginini were sensitive to pefloxacin, erythromycin and lincospectin (0.024-0.19 ug/mI), while Rovipneumoniae was fess susceptible (0.097-0.39 ug/ml). Ampicillin and streptomycin had the lowest M.I.C. values for all the examined isolates (0.78-3.12 µg/m1).