The objective of the present study was to evaluate the kinetic of antibodies against the Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) in 30 of a group of 200 pigs in a commercial farm in Lima, Peru. Blood samples were collected at 32, 61 and 135 days of age for detecting antibodies against PRRSV by indirect ELISA. In addition, theoccurrence of respiratory clinical signs was daily recorded in the total group of 200 animals including the 30 animals of the study. The 26.7% (8/30) of pigs had antibodies against PRRSV at 32 days of age and only one at 61 days of age, while 96.7% (29/30) had antibodies against PRRSV at 136 days of age with S/P values between 0.4 and 2.0. Non respiratory problems were recorded. The presence of antibodies and age of animals was statistically associated (p<0.05).