Persistent thin endometrium is a major challenge in ART. Couple phase cycle cancellations due to this problem. There are many methods which have come up recently to resolve this challenge. One of such treatment involves PRP instillation. This study was conducted to evaluate the effect of PRP in persistently thin endometrium. Design: Prospective interventional study Materials &methods : Thirtyone women who were scheduled for FET , and were diagnosed to have persistently thin endometrium were involved in this study. These patients also had 2 or more cycle cancellations. In addition to HRT with estradiol valerate, 0.5 ml of autologous PRP was instilled into uterine cavity 48-72 hours before progesterone exposure. Frozen embryo transfer was performed when the endometrium reached an optimal pattern in thickness & vascular it you. Results: Mean endometrial thickness was increased from 5.83 to 7.13 mm post PRP. Power Doppler showed good vascularity , reaching the zones 3 & 4 of endometrium. Positive beta Hcg was 73.3%. Twenty two pregnancies documented.