Objective To study the impact of blood clots in the oocyte-corona-cumulus complexes (OCCC) during in vitro fertilization and embryo transfer (IVF-ET). Methods The OCCCs were harvested from the patients undergoing long protocol ovarian hyperstimulation. The OCCCs with blood clots removed or not, were randomly grouped into A or B. The OCCCs without blood clots were group C (the control). Results The patient’s age, infertility duration, the average GN consumption, the average days of superovulation and an average number of harvested oocytes showed no significant difference in the 3 groups. The fertilization rate and 2PN rate in group A were the highest, which were 85.4% and 71.1%, respectively, followed by group C, which were 77.5% and 64.9%, respectively. The lowest fertilization rate and 2PN rate were in group B, 75.8% and 62.2%, respectively. Those in group A were significantly higher than those in groups B and C (P<0.01), while there was no significant difference between group B and group C . The implantation rates and pregnancy rates showed no significant difference in the 3 groups after transplantation, even if group A got the highest rate among the 3 groups. Conclusion Removing the blood clots in OCCC can improve the outcome of IVF-ET without increasing the cost and complexity of the operation. Objective To study the impact of blood clots in the oocyte-corona-cumulus complexes (OCCC) during in vitro fertilization and embryo transfer (IVF-ET). Methods The OCCCs were harvested from the patients undergoing long protocol ovarian hyperstimulation. The OCCCs with blood The patients’ age, infertility duration, the average GN consumption, the average days of superovulation and an average number of harvested The fertilization rate and 2PN rate in group A were the highest, which were 85.4% and 71.1%, respectively, followed by group C, which were 77.5% and 64.9%, respectively. The fertilization rate and 2PN rate in group A were the highest, which were 85.4% and 71.1% respectively Fertilization rates and 2PN rates were in group B, 75.8% and 62.2%, respectively. Those in group A were significantly higher than those in groups B and C (P <0.01), while there was no significant difference between group B and g roup C. The implantation rates and pregnancy rates showed no significant difference in the 3 groups after transplantation, even if group A got the highest rate among the 3 groups. Conclusion Removing the blood clots in OCCC can improve the outcome of IVF-ET without increasing the cost and complexity of the operation.