Purpose To investigate the impact of late follicular phase serum estradiol (E 2 ) levels on implantation and pregnancy outcomes of cleavage stage cryopreserved/thawed embryos transferred in programmed cycles with exogenous hormonal replacement. Methods Retrospective cohort analysis of IVF patients with transfer of cryopreserved-thawed day-3 embryos in E 2 and progesterone (P4) supplemented cycles (n=208 cycles). Main outcome measures: implantation and pregnancy rates according to late follicular phase serum E 2 levels and early secretory phase E 2 /P4 ratios. Results Logistic regression performed for embryo implantation and for pregnancy outcome in relation to E 2 (day 15), P4 (day 15 and 16), before (crude analysis) and after adjustment (adjusted analysis) for baseline characteristics (including age, BMI, serum basal cycle day 3 FSH levels, embryo quality, endometrial lining thickness) showed no significant association. Similarly, ROC analysis showed no impact of cycle day 16 E 2 /P4 ratio. Conclusions Neither late follicular phase serum E 2 nor the early E 2 /P4 ratio were able to predict implantation or pregnancy outcome of day-3 cryopreserved-thawed embryos transferred in artificially programmed cycles.