The objective of the present study was to evaluate the accuracy of transrectal ultrasonography as a method of pregnancy diagnosis at an early stage in graded murrah buffaloes. 30 inseminated buffaloes were utilized and pregnancy diagnosis was commenced on day 20, 25 and 30 post breeding. Positive diagnosis of pregnancy was based on the presence of an anechoic round area of varying size in the lumen of an echogenic uterine lumen representing the fluid filled allantoic cavity termed as the embryonic vesicle. The presence of an embryo within the embryonic vesicle was confirmed by observing an echogenic area with rhythmic pulsation representing heartbeats. The average lengths of embryonic vesicle on day 20, 25 and 30 were 0.415 ± 0.05, 1.116 ± 0.107 and 1.85 ± 0.068 cm, respectively and the average lengths of

embryo on day 25 and 30 were 0.45 ± 0.064 and 1.05 ± 0.086 cm, respectively. Sensitivity was lower on day 20 and 25 being 50 and 75%, respectively when compared to day 30 which was 100%. The overall accuracy increased as the pregnancy advances and was observed to be 100% from day 30 onwards. It was confirmed that early pregnancy diagnosis using ultrasonography can be done effectively from day 25 post insemination.