Abstract: About 553 Dairy cattle carcasses were inspected at a slaughter house in Baja California, out of 298 showed gross tuberculosis-like lesions. Microscopic examination of tissues using H and E and acid fast staining revealed 268 suspect cases. Of the 268, 104 were culture positive while 123 were PCR positive for M. tuberculosis complex. A total of 70 samples were culture and PCR positive and an additional 53 samples were PCR positives but culture negative. Thus PCR increases the rate of detection and will be a useful tool for control programs especially when considering the lower sensitivity of diagnosis by bacteriological culture, the occupational risk, technical difficulties with the protocol and the prolonged time of incubation.