Objectives: Study the effect of adding a delayed blastocyst to a transferred good quality one on ICSI cycle outcomes. Study design: Prospective cohort study. Participants/materials, setting, methods: 90 infertile patients aged from 20 - 35 years due to mild male factor, unexplained infertility or tubal factor. Patients with PCOS, endometriosis, RIF, poor responder and azoospermia were excluded. Setting: Duration 6 months from October 2019 to April 2020 in a private IVF center in Egypt. 30 cases were subjected to elective single embryo transfer and the other 60 with two embryo transfers, one good quality and another poor quality blastocyst. Results: (clinical pregnancy rate) was comparable between the two groups, being 47.7% and 36.7% in SET and DET groups respectively (p = 0.361). Miscarriage and ectopic pregnancy rate were observed in 10% of the cases pregnant after SET (group I) and in only 6.7% of the cases pregnant after DET (group II) denoting no significant statistical difference between the two groups. The highest incidence was missed miscarriages in the two groups and ectopic pregnancy was observed only in one case in group II (DET). Twin pregnancy occurred in 22% of pregnant females in the second group. Late pregnancy complications in the form of preterm labour, premature rupture of membrane and preeclampsia occurred mainly in pregnant females in the second group 18%. Conclusion: Neither adding a delayed blastocyst negatively affected the good one nor affected the live birth rate but increased multiple pregnancy rates.