During august to november 1992, a phenomenon of abortion occured in 17 cases of buffaloes aged from 4 - 6 years old at different stages of pregnancy at different localities at Assiut Governorate. The clinical condition of each aborted buffalo supported by the results obtained from serological and bacteriological examinations ensured the cause of abortion to be due to Brucella infection. Bacteriological examinations revealed 10(58.82%) of local brucella isolates recovered from buffaloes' milk. Isolates were belonged to one strain of Brucella melitensis biotype 3. Sero-bacteriological examinations proved that the abortus Bang ring test was more specific, highly susceptible and reliable test in diagnosis of buffalo-brucellosis during time of abortion, where, 52. 94% of positive brucella cultures were detected in bufalloes' milk. Brucella micro-organisms represented 58. 82% of the causitive agents of abortion in buffaloes according to isolation of brucella organisms from buffaloes' milk.