This study was conducted to assess the situation of infection with metritis, mastitis, agalactia syndromes (M.M.A) in the sow after breeding and effect of these syndromes to reproductive productivity of the sow at the breeding farms of 4 provinces in the Red River Delta. The studied result showed that the infection rate of M.M.A in the sow herd in general was 48.92 percent, the highest infection rate was at the 5th breeding time onward, the lowest infection rate was at the 2nd, 3rd breeding times
the highest infection rate was in summer (34.57 percent) and the lowest infection rate was in autumn (25.53 percent). Period of rut in post-weaning of the infected sows was longer than that of the normal sows. The indexes such as: the rate of re-ruting, the conceive rate, the average of post weaning piglet numbers per sow and weight of the 21 days old piglets from the M.M.A infection sows were all lower than the respective indexes from the normal sows with significant difference (P0,05).