SUMMARY The present study was carried out on 19 non pregnant regular cycling lactating and healthy buffalo-cows. They aged 5-8 years and gave from 3-6 births. During estrus (day 0), day 8 and day 21 after estrus blood samples
were taken from each buffalo-cow and serum progesterone was determined by radioimmuno-assay. Each buffalo-cow manifested estrus was subjected to natural service at the suitable time by a sound good fertile buffalo bull and isolated for 60 days till rectal palpation was performed to confirm pregnancy. Non pregnancy can be predicted with a high degree of accuracy (85.7%) at 21 days after service. The overall accuracy of predicting pregnancy by serum progesterone test in buffaloes was 70%.