Objective: The aim of this study was to assess whether the time from the menstrual day at embryo transfer to expected menstrual cycle (TETEMC) is associated with the implantation in women with regular cycles or not. Materials and Methods: Forty women with successful implantation and forty women without implantation with regular cycles were randomly selected from prospectively collected database of assisted reproductive technology clinic of Zeynep Kamil Women And Children's Health Training and Research Hospital. TETEMC was calculated for each case to assess relationship with the successful implantation. Results: Comparison of groups revealed significant differences with regard to TETEMC and the menstrual period (p < 0.05). In ROC analyses both the TETEMC (AUC=0.824, p < 0.001) and the menstrual period (AUC=0.797, p < 0.001) were significant predictors for clinical pregnancy. Cut off value for the menstrual period was found to be 27.5 days with 82.6% sensitivity and 65% specificity. Cut off value for TETEMC was 11.5 days with 75% sensitivity and 63.2% specificity. Conclusion: Longer menstrual cycle and the TETEMC seem to be associated with the implantation failure.