The involvement of one or another autoantibody in reproductive failure have long been thought to be through post-implantation thrombosis and/or peri-implantation trophoblast dysfunction and/or maternal hormonal imbalance. It can be postulated that the embryo may be a direct target for some autoantibodies prior to implantation. Mouse embryos have been labelled and cultured with affinity purified immunoglobulin (IgG) and IgA from positive for antiphospholipid antibody sera, as well as IgG from positive for antinuclear antibody sera and positive for antithyroid antibody sera. Intact IgG and IgA from healthy individuals were used as controls. All embryos cultured with purified antiphospholipid IgG or IgA, and anti-nuclear IgG exhibited strong immunofluorescence. No difference in fluorescent intensity was observed whether antiphospholipid or anti-nuclear antibodies were used, but the pattern of antibody distribution seemed to be different. Antiphospholipid IgG was more dominant on the zona pellucida, while antiphospholipid IgA and antinuclear IgG had predominant distribution on the embryonic cells. None of the embryos cultured with antithyroid IgG or with control immunoglobulins showed strong immunofluorescence. Embryos cultured with purified antiphospholipid and antinuclear immunoglobulins experienced significant growth impairment or death compared to those cultured with antithyroid or control immunoglobulins.