Abstract Study question Can a second successive-ejaculate (SSE) be an option for patients with poor sperm parameters (PSPs) on ovum pick-up (OPU)-day who prefer to undergo conventional-IVF (c-IVF)? Summary answer SSE can be a valid option for patients with PSPs who do not wish to undergo ICSI as an assisted reproductive technology (ART) treatment. What is known already ART is applied when first-line treatment for infertility (timed intercourse or intrauterine insemination) is unsuccessful. The male partner is requested to follow ejaculatory abstinence, which according to the WHO guidelines is 2-7 days, while ESHRE recommends 3-4 days. Among these couples there are cases that require ICSI due to semen analysis with PSPs on the day of OPU. However, some couples are reluctant to undergo ICSI and prefer c-IVF as a treatment method. For those cases, we request a second semen sample on the same day (time interval: 1-4 h) and c-IVF is performed using the two ejaculates combined. Study design, size, duration This is a single-centre retrospective study employing 212 semen from male partners with PSPs in the first semen collection on the OPU-day and subsequently, an SSE was requested in order to perform c-IVF according to patients’ wishes. The data were collected from May 2006 to October 2023 in our clinic (SSE-group). The Control group included 271 semen samples from men where c-IVF was conducted using one ejaculate from January to December 2021 in our clinic. Participants/materials, setting, methods The sperm parameters were analysed according to the WHO manual for the examination and processing of human semen and compared between the first and second ejaculates in the SSE-group. Fertilisation rate (FR), percentage of clinically utilised embryos and clinical pregnancy rate were compared between the SSE-group and the Control group. The SSE-group had 254 ART-cycles and the mean maternal age was 36.8±4.9y.o. The Control group included 432 ART-cycles and the mean maternal age was 38.1±5.2y.o. Main results and the role of chance In SSE-group the semen volume of the first ejaculate was significantly higher compared to the second ejaculate (P< 0.0001). The sperm concentration and sperm motility were significantly higher in the second ejaculate compared to the first one (P<0.0001). In the same fashion, the total-motile sperm-count was significantly higher in the second ejaculate compared to the first (P=0.01). All the semen parameters in the Control group were significantly higher compared to both first and second ejaculates from the SSE-group (P<0.00001). The normal FR was significantly higher in the Control group compared to the SSE–group (P<0.01). On the other hand, there was no significant difference in the percentage of embryos that could be utilized (cryopreserved + freshly-transferred) between the two groups (P=0.218). Pregnancy rate for fresh embryo transfers (ETs) was significantly higher in the SSE-group compared to the Control (P=0.005), while there was no significant difference between the two groups for pregnancy rate for frozen/thawed ETs (P=0.728). The main strength of our study is that the utilisation of the SSE combined with the first ejaculate did not decrease the pregnancy rate for the couples with PSPs that wished to follow c-IVF as their treatment and it could actually provide an effective option for them. Limitations, reasons for caution SSE may improve the sperm parameters and give the opportunity to infertile couples to undergo c-IVF according to their wish. However, since the FR was lower in the SSE-group, it is of paramount importance to provide sufficient explanation to those couples and obtain their consent when requesting an SSE. Wider implications of the findings Overall, SSE had positive effect to a large number of parameters evaluated in this study. Additionally, the rate of utilised embryos was similar between the two groups. Two successive-ejaculates combined can be employed without any negative impact for couples with PSPs on the OPU-day that are reluctant to undergo ICSI. Trial registration number not applicable