Scientific knowledge on the molecular changes that occur during the window of implantation is fundamental for the understanding of human reproduction. To gain a global molecular understanding of human endometrial receptivity, we have compared gene expression profiles of pre-receptive (day LH + 2) versus receptive (LH + 7) in well characterized human endometrial biopsies. The samples were analyzed using the Affymetrix HG-95A array, a high density oligonucleotide microarray comprising more than 12,000 genes. In this work, we present part of our results and a comparison with similar works published in the literature. Identified genes include not only genes previously documented to be involved in implantation but also genes for which a role in endometrial receptivity, or even endometrial expression, has not been previously described. Collectively, these studies identify new candidate markers that may be used to diagnose unequivocally the receptive endometrium.