uC31 integrase, a site-specific recombinase, can effectively mediate foreign genes bearing anattBsequence integrated into pseudoattPsites. We have previously identified two pseudoattP sites, BpsF1 and BpsM1 from the bovine genome. In this study, two new pseudoattPsites, BF4 and BF10, were discovered using half-nested inverse PCR from cow fibroblasts.