Micoplasmosis is a highly economic disease of Poultry. To prevent mycoplasmosis a poultry person should have clear knowledge about the present antibody status against Mycoplasma spp. by the routine seromonitoring protocol. Mycoplasmosis can control effectively by serosurveillance. The serum antibody can detect easily by indirect enzyme linked immune sorbent assay (iELISA) and rapid plate agglutination (SPA) tests. The book may be helpful to guide the seroprevalence study and antibody test procedure of layer poultry on practical basis.