The purpose of this study was to detect Mycobacterium bovis in cattle(serum, milk, lung, lymph node) by PCR. Nineteen samples from 7 skin test-positive cattle were analyzed. The amplified band of IS6110 by PCR was detected from 2 samples in lung and Iymph node. But the sensitivities of the present methods for detecting M bovis in milk and serum are deficient. Because the PCR sensitivity has been shown to be hindered by the method used to isolate the nucleic acid target. PCR-based methods have the potential to be faster, more accurate, and the most efficient means of detecting M bovis. The detection of M bovis by PCR will contribute to the more efficient detection and control of tuberculosis.