Global warming due to climate change is likely to aggravate the thermal/heat stress in buffaloes, affecting their reproductive and productive performance. Stress levels during a day have been worked out using Temperature Humidity Index (THI) calculated from dry bulb and wet bulb temperature monitored every ten minutes during 2005-07. The analysis revealed that THI starts increasing in afternoon from February onwards and exceed 75 for 2-3 h in the afternoon from March onwards. For more than 1500 h during the year THI ranges 76-80 and for other 1500 h between 81-85. THI exceeding 85 (86-95) are observed during May for more than 115 h and total number of hours increases to 300-350 during July and August. Climate change scenarios constructed for India revealed that maximum temperature (T max) rise of 4.54, 4.42, 3.07 and 4.38˚C, respectively during Dec-Feb, Mar-May, Jun-Aug and Sep-Nov and very less change in precipitation is likely to increase uncomfortable days (THI>80) from existing 40 days (10.9% of the year) to 104 days (28.5% of the year) for a projected temperature rise as per Had CM3-A2 scenario and 89 days for an average temperature rise of 2.95˚C as per B2 scenario for time slices 2079-2099. Increased number of heat stress days with THI >80 (by 160 % for A2 scenario) are likely to have a negative impact on estrus symptoms, duration and conception of buffaloes. Data analysis showed that buffaloes have a typical rhythmic pattern with one or two peaks during the year and low reproductive activity during summer. A higher thermal stress on lactating buffaloes is likely to have a negative impact on gonadal functions. The study concluded that likely temperature rise due to global warming may negatively impact reproductive functions of buffaloes and increase the incidence of silent estrus, short estrus and change reproductive rhythm and production efficiency of buffaloes.