This study was carried out to assess buffalo-bulls libido and mating capacity using modified serving capacity test (M.S.C.T) and ultrasonographic appearance of the testis and accessory sex glands. Six buffalo-bulls were used throughout the study. The current results showed that the dominant bulls had larger scrota1 circumference (SC) and earlier reaction time and good semen characteristics. The ultrasonographic examination revealed a significant variation between the testicular and accessories dimensions of dominant and dominated bulls for length, width and thickening. The ultrasonographic appearance showed changes in the echo-texture of the genital tracts of buffalo-bulls during various physiologic status and results were recorded and tabulated. From the present study it could be concluded that M.S.C.T offers a good idea to assess buffalo-bulls libido and mating ability. Also, the ultrasonography could be used accurately to evaluate the testicular and accessory sex glands of buffalo-bulls and recognition of abnormal conditions of these organs.