Staff sickness absenteeism and presenteeism (attending work while unwell) incur high costs to the NHS, are associated with adverse patient outcomes and have been exacerbated by the COVID-19 pandemic. The main causes are mental and musculoskeletal ill health with cardiovascular risk factors common. To undertake a feasibility study to inform the design of a definitive randomised controlled trial of the effectiveness and cost effectiveness of a health screening clinic in reducing absenteeism and presenteeism amongst the National Health Service staff. Individually randomised controlled pilot trial of the staff health screening clinic compared with usual care, including qualitative process evaluation. Four United Kingdom National Health Service hospitals from two urban and one rural Trust. Hospital employees who had not previously attended a pilot health screening clinic at Queen Elizabeth Hospital Birmingham. Nurse-led staff health screening clinic with assessment for musculoskeletal health (STarT musculoskeletal; STarT Back), mental health (patient health questionnaire-9; generalised anxiety disorder questionnaire-7) and cardiovascular health (NHS health check if aged ≥ 40, lifestyle check if < 40 years). Screen positives were given advice and/or referral to services according to UK guidelines. The three coprimary outcomes were recruitment, referrals and attendance at referred services. These formed stop/go criteria when considered together. If any of these values fell into the 'amber' zone, then the trial would require modifications to proceed to full trial. If all were 'red', then the trial would be considered unfeasible. Secondary outcomes collected to inform the design of the definitive randomised controlled trial included: generalisability, screening results, individual referrals required/attended, health behaviours, acceptability/feasibility of processes, indication of contamination and costs. Outcomes related to the definitive trial included self-reported and employee records of absenteeism with reasons. Process evaluation included interviews with participants, intervention delivery staff and service providers. Descriptive statistics were presented and framework analysis conducted for qualitative data. Due to the COVID-19 pandemic, outcomes were captured up to 6 months only. Three hundred and fourteen participants were consented (236 randomised), the majority within 4 months. The recruitment rate of 314/3788 (8.3%) invited was lower than anticipated (meeting red for this criteria), but screening identified that 57/118 (48.3%) randomised were eligible for referral to either general practitioner (81%), mental health (18%) and/or physiotherapy services (30%) (green). Early trial closure precluded determination of attendance at referrals, but 31.6% of those eligible reported intending to attend (amber). Fifty-one of the 80 (63.75%) planned qualitative interviews were conducted. Quantitative and qualitative data from the process evaluation indicated that the electronic database-driven screening intervention and data collection were efficient, promoting good fidelity, although needing more personalisation at times. Recruitment and delivery of the full trial would benefit from a longer development period to better understand local context, develop effective strategies for engaging with underserved groups, provide longer training and better integration with referral services. Delivery of the pilot was limited by the impact of COVID-19 with staff redeployment, COVID-research prioritisation and reduced availability of community and in-house referral services. While recruitment was rapid, it did not fully represent ethnic minority groups and truncated follow-up due to funding limitations prevented full assessment of attendance at recommended services and secondary outcomes. There is both a clinical need (evidenced by 48% screened eligible for a referral) and perceived benefit (data from the qualitative interviews) for this National Health Service staff health screening clinic. The three stop/go criteria were red, green and amber; therefore, the Trial Oversight Committee recommended that a full-scale trial should proceed, but with modifications to adapt to local context and adopt processes to engage better with underserved communities. This trial is registered as ISRCTN10237475. This award was funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research programme (NIHR award ref: 17/42/42) and is published in full in Health and Social Care Delivery Research; Vol. 12, No. 23. See the NIHR Funding and Awards website for further award information.