What are the knowledge, perceptions and attitudes towards fertility and elective oocyte cryopreservation (OC) for age-related fertility decline (ARFD) in women in the UK? Awareness of OC for ARFD has reportedly improved compared to studies carried out almost a decade ago, but inconsistencies in knowledge remain regarding the rate of miscarriage amongst specific age groups, the financial costs and optimal age to undergo OC for ARFD. The age of first-time motherhood has increased amongst western societies, with many women of reproductive age underestimating the impact of age on fertility. Further understanding of women's awareness of their fertility, the options available to preserve it and the barriers for seeking treatment earlier are required in order to prevent the risk of involuntary childlessness. A hyperlink to a cross-sectional survey was posted on social media (Instagram) between 25 February 2021 and 11 March 2021. Women from the general population aged 18-50 years were invited to complete the survey. In total, 5482 women fulfilled the inclusion criteria and completed the survey. The mean age of participants was 35.0 years (SD 10.25; range 16-52). Three quarters (74.1%; n = 4055) disagreed or strongly disagreed they felt well informed regarding the options available to preserve their fertility, in case of a health-related problem or ARFD. The majority overestimated the risk of miscarriage in women aged ≥30 years old, with 14.5% correctly answering 20%, but underestimated the risks in women ≥40, as 20.1% correctly answered 40-50%. Three quarters (73.2%; n = 4007) reported an awareness of OC for ARFD and 65.8% (n = 3605) reported that they would consider undergoing the procedure. The number of women who considered OC for ARFD across age groups were as follows: 18-25 (8.3%; n = 300), 26-30 (35.8%; n = 1289), 31-35 (45.9%; n = 1654), 36-40 (9.6%; n = 347), 41-45 (0.3%; n = 13), and 46-50 (0.1%; n = 2). The majority of women (81.3%; n = 4443) underestimated the cost of a single cycle of OC for ARFD (<£5000). Furthermore, 10.4% (n = 566) believed a single cycle would be adequate enough to retrieve sufficient oocytes for cryopreservation. Approximately 11.0% (n = 599) believed OC for ARFD may pose significant health risks and affect future fertility. Less than half agreed or strongly agreed that the lack of awareness regarding OC for ARFD has impacted the likelihood of pursuing this method of fertility preservation further (41.4%; n = 2259). Results from cross-sectional studies are limited as interpretations made are merely associations and not of causal relationships. The online nature of participant recruitment is subject to selection bias, considering women with access to social media are often from higher socioeconomic and education backgrounds, thus limiting generalizability of the findings. Further education regarding the financial costs and optimal age to undergo elective OC to increase the chances of successful livebirth are required. Clinicians should encourage earlier fertility counselling to ensure that OC is deemed a preventative measure of ARFD, rather than an ultimate recourse to saving declining fertility. No funding was required for this article. There are no conflicts of interests to declare. N/A.