What do fertility staff and patients think is bad news in fertility care? Staff and patients agree bad news is any news that makes patients less likely to achieve parenthood spontaneously or access and do successful treatment, but their appraisals of how bad the news is are differently influenced by specific news features and the context of its delivery. Bad news is common in fertility care, but staff feel unprepared to share it and four in 10 patients react to it with unanticipated emotional or physical reactions. Research has paid much attention to how bad news should be shared, but considerably less to what news is perceived as bad, despite the fact this may dictate elements of its delivery. Two cross-sectional, online, mixed-method surveys (active 7 January-16 July 2022) were distributed to fertility staff and patients across the UK and Europe. Staff inclusion criteria were being a healthcare professional working in fertility care and having experience of sharing bad news at least once a month. Patients' inclusion criteria were being adults and having had a conversation in which staff shared or explained bad news concerning their fertility care within the last 2 months. Surveys were created in English using Qualtrics, reviewed by patients and healthcare professionals, and distributed via social media, Prolific, fertility organizations, and scientific societies. Patients were asked, regarding the last time bad news were shared with them, 'What was the bad news?' and 'What other news would you consider bad news in fertility care?'. Staff were asked to 'List the three most challenging topics of bad news you share with your patients'. Staff and patient data were separately thematically analysed to produce basic codes, organized into sub-themes and themes. Themes emerging from patients' and staff data were compared and synthesized into meta themes. Three hundred thirty-four staff accessed the survey, 286 consented, and 217 completed (65% completion rate). Three hundred forty-four patients accessed the survey, 304 consented, and 222 completed (64% completion rate). Eighty-five percent of participants were women, 62% resided in Europe, and 59% were in private care. Average staff age was 45.2 (SD = 12.0), 44% were embryologists or lab technicians, 40% were clinicians (doctors, consultants, or physicians), and 8% nurses or midwifes. Average patient age was 32.2 (SD = 6.4) and 54% had children. Staff answers originated 100 codes, 19 sub-themes and six themes. Patients' answers produced 196 codes, 34 sub-themes, and 7 themes. Staff and patient themes were integrated into three meta-themes reflecting main topics of bad news. These were Diagnosis and negative treatment events and outcomes, Inability to do (more) treatment, and Care and patient factors disrupting communication. Staff and patients agreed that some news features (uncertain, disruptive, definitive) made news more challenging but disagreed in relation to other features (e.g. unexpected/expected). Patient factors made bad news more challenging to staff (e.g. difficult emotions) and care factors made bad news more challenging to patients (e.g. disorganized care). Participants were self-selected, and most were women from private European clinics. Questions differed for staff and patients, focused on subjective perceptions of news, and did not measure news impact. The badness of fertility news is not only a product of the extent to which the news compromises parenthood goals but also of its features (timing, nature, number) and the context in which the news is delivered. Guidance on sharing bad news in fertility care needs to go beyond easing the process for patients to also consider staff experiences. Guidance may need to be tailored to news features and context. Cardiff University funded the research. S.G., J.B., O'.H., and A.D. report funding from the Higher Education Funding Council for Wales and the European Society for Human Reproduction and Embryology (ESHRE) to develop fertiShare: a sharing bad news eLearning course for fertility care. fertiShare will be distributed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International Licence (CC BY-NC-SA 4.0). No other conflicts are reported in relation to this work. N/A.