Recurrent implantation failure (RIF) represents a great challenge in current reproductive medicine. RIF as a term stands for the failure of implantation with repeated transfers of good quality embryos. Embryo implantation is a critical phase of in vitro fertilization (IVF) procedures. An effective interaction between a high-quality embryos and a receptive endometrium is necessary for a successful pregnancy. Chronic endometritis (CE) is considered an important cause for RIF as it has high prevalence rate among women with recurrent ICSI failure. CE is defined as a persistent inflammatory disorder affecting the endometrial lining, which is characterized by edematous change of the superficial endometrial with high stromal cell density and dissociated maturation between epithelium and stroma, in addition to infiltration of endometrial stroma by plasma cells. Hysteroscopy and endometrial biopsy for plasma cell detection are the two mainly used methods for diagnosis CE. Focal or diffuse endometrial hyperaemia, stromal edema, and micropolyps are the most recognized hysteroscopic findings used to diagnose CE. The detection of plasma cells in endometrial samples is preferred to be done with CD138 immunohistochemistery (IHC).