Ruminant placental lactogens (PL) are members of the growth factor/prolactin (GH/PRL) family. They are synthesized by trophectodermal binucleate cells. Until now, there was no information exists about profiles of PL concentration during gestation in swam buffalo. The aim of the present study was to evaluate the ability to detect PL in buffalo fluids by using bovine PL (bPL) antibody and to profile of it during gestation. Samples were collected in slaughterhouse immediately after animal slaughter. The fetuses were measured after heart blood collection for estimate time pregnant. A bPL radioimmunoassay system was used to determine the bPL concentrations in the buffalo samples. The recombination bPL molecules were radio-iodinated with 125I-Na by using the Lactoperoxidase method. In this RIA system, the minimum detected value was 0.068 ng/mL and the binding competition curves of bovine PL standard and buffalo fluids dilution using bovine PL antibody was paralleled in all kinds of samples. Concentrations of buffalo PL were presented the highest in fetal plasma (1.35 ng/mL) and the lowest in allantoid fluid (0.42 ng/mL) (P 0.05). Study of the biology of PL in buffalo has proved more correlation between the levels of concentration of PL in the all buffalo fluids and pregnant time (R2 0.92). In conclusion, the results provide preliminary results about concentrations of PL in buffalo fluids during gestation.