A total of 22 buffaloes (22 / 150) at El-Minia governmental farm manifested fever (40 C), anorexia and enlargement of the superficial lymph nodes (precrural and prescapular nodes). Theileria parasite was detected in the blood films prepared from these animals. After application of the convenient treatment, parasitaemia disappeared but the relevant cases remained debilitated and thereafter 8 cases died. Examination of the biopsy samples taken from the superficial lymph nodes of the treated animals revealed schizont-infected lymphoblasts. This indicated a carrier state of theileriasis. The condition was confirmed by the pathomorphology of the affected lymph nodes. The pathologica picture was that of the late stage of theileria infection. The obtained results indicated that the method of lymph node biopsy is a reliable mean for the detection of theileria-carrier animals.