Endometrial receptivity is imperative to achieving pregnancy in humans. A disruption in the development of endometrial receptivity is responsible for recurrent implantation failures (RIF) of endometrial origin. To further understand the molecular mechanisms behind the endometrial receptivity process, we used the 8-plex isobaric tag for relative and absolute quantitation (iTRAQ) method to compare and quantify the proteomes from endometrial biopsies of three different endometrial statuses (fertile women, IUD carriers and RIF patients). Overall, iTRAQ allowed to identify 1,889 non-redundant proteins. Of these, 188 were differentially expressed proteins (DEP) (p-value < 0.05) among the three endometrial groups. Pairwise comparisons revealed 133 significant DEP in fertile vs. IUD carriers and 158 DEP in RIF vs. IUD carriers. However, no DEP were identified between fertile and RIF patients. Western blot validation of three DEP involved in endometrial receptivity (Plastin 2, Lactotrasferrin, and Lysozyme) confirmed our iTRAQ results. Moreover, functional KEGG enrichment revealed that complement and coagulation cascades and peroxisome were the two most significant pathways for the RIF vs. IUD comparison and ribosome and spliceosome for the fertile vs. IUD comparison, as possible important pathways involved in the endometrial receptivity acquisition. Our findings confirm that an IUD introduces numerous changes in the endometrial protein profile when compared to fertile and RIF endometria, revealing some key proteins involved in endometrial receptivity. The lack of DEP between fertile and RIF patient endometria suggest either that idiopathic RIF may not have an endometrial origin, with other as-yet-unknown factors involved.