Antiphospholipid antibodies (aPL) are an established cause of recurrent pregnancy loss. As defective embryonic implantation is a common link between unexplained infertility and recurrent miscarriage, interest has focused on the potential relationship between aPL and implantation failure after in vitro fertilization and embryo transfer (IVF-ET). This review critically examines the published data to determine whether women undergoing IVF-ET should be routinely screened for aPL. Although most studies have reported an increased prevalence of aPL among women undergoing IVF-ET, prospective studies examining the effect of aPL on the outcome of IVF-ET demonstrate that these antibodies do not significantly affect either the implantation or ongoing pregnancy rates. The increased prevalence of aPL among women with infertility is therefore likely to be part of a generalized autoimmune disturbance associated with infertility. Hence routine screening for aPL among women undergoing IVF-ET is not warranted and therapeutic interventions should be used only in well designed randomized controlled trials.