To study the effect of dietary monensin supplementation on the blood metabolite and reproductive performance of suckled buffalo-cows as well as the weight gain of their calves, a total of 14 multiparous pregnant buffalo cows were divided into two groups 7 per each. One group (control) fed on pelleted concentrate containing no monensin sodium, the other group (monensin) fed a similar concentrate supplemented with 150 and 200 ppm\head\day during prepartum (70 days) and postpartum (120 days) period, respectively. Buffalo-cows in the monensin group consumed less forages (dry matter) during late pregnancy and early lactation by 4.82 and 6.98 % respectively than did the control group. Monensin feeding didn't affect calf birth weight, but significantly (p < 0.05) improved their weight at 120 days of age. Meanwhile, body condition score of buffalo-cows at calving and at conception was significantly (p < 0.05) increased in the monensin group compared with the control one. Buffalo-cows fed on monensin have a significantly higher plasma propionate(P<0.05) and insulin(P<0.05) concentrations and a significantly lower acetate (P<0.05), acetate : propionate ratio (P<0.05) and blood urea nitrogen (P<0.05) concentrations than that fed on control diet. Glucose levels were not affected by treatment. There was no significant difference between control and monensin group in respect to uterine involution. However, the postpartum interval was significantly (P<0.01) decreased in buffalo cows supplemented with monensin compared to that recorded with control group (30.60 Vs 56.40 days). Pregnancy rate (up to 120 d postpartum) was higher in monensin-fed buffalo-cows(86% (617)) than control (52%(417)). Meanwhile, days open were significantly (P<0.01) decreased in monensin group compared with control one (90.00 Vs 115.00 days). It can be concluded that monensin can be safely used as feed supplement at a level of 150 and 200 mg/head/day during pre-and postpartum period, respectively for buffalo-cows to shorten the postpartum period, to improve their fertility rate and to enhance the weight gain of their suckling calves.