Abstract - The purposes of this study were to determine the effects of follicular status (number and size) at beginning of estrus induction, the timing of estrus synchronization and insemination (morning vs. evening), season (de- creasing day length vs. increasing day length) in pregnancy rate of synchronized Bangladeshi water buffaloes. A total of 79 lactating indigenous water buffalo cows were used and synchronized with modified Ovsynch pro- tocol (GnRH+PGF2?+GnRH+GNRH) for estrus detection. Buffaloes were divided into two groups as Group-1 (n=54) and Group-2 (n=25) according to day length. Each group was subdivided as AM and PM according to the time of administration of hormones for synchronization protocols. AI was performed using frozen-thawed semen. Pregnancy was confirmed after watching viable embryos at day 40 days post-AI by trans-rectal ul- trasonography. The overall pregnancy rate was 56.25% in this study. A higher pregnancy rate (77.7%) was observed in buffaloes of Group-1 where synchronization was conducted in the morning in September (during decreasing day length). Follicular size at the time of AI significantly (P < 0.05) affected the pregnancy rate. The findings of the study suggest that follicular size, time of AI and season should be considered during estrus induction for the improvement in the pregnancy rate of water buffaloes when inseminated with frozen-thawed semen.