Introduction Porcine Reproductive and Respiratory Syndrome (PRRS) is a disease that produces devastating effects which has plagued the pig industry in the last three decades 1 . After infection, antigen-specific humoral immunity first appears at about 7-10 days post infection, and this can be detected by conventional serological tests 2 . In Venezuela, serological studies shows a range from 42% to 90% of prevalence 3 . However, we have not data about the movement of PRRS antibodies through reproductive herd or downstream in the pig farms hitherto. For this reason we have investigated the kinetics of PRRSV-specific antibodies in several pig farms under tropical environment by using Elisa test. Materials and Methods Sera lab data collected from twenty nine pig farms belonging to 6 states were used to this study. Sampling method include those from the breeding herd and downstream pigs. Samples range were from 25 to 83 sera per farm. Sera from breeding herd were grouped according to their conditions, ie, gilts, parity 1 to 6 or greater. In nursery-finish, sera were collected in pig of 3 to 15, 17 to 21 weeks of age. All sera were processed to by using Elisa test HerdChek 2XR PRRS and/or HerdCheck 3X Ab PRRS (Idexx Laboratories Inc, USA). Results 1297 serum samples were analyzed during a two year period. We found PRRS prevalence in all farm breeding herds, we lesser positivity in parity 5 and parity ≥ 6 , 13,7% and 8,9%, respectively (Table 1). In pigs, positive S/P values were detected in every age. S/P values and positivity (ranging 30% to 60%) were high in pigs on 7 to 12 weeks of age, then a new raise of S/P