BackgroundThe increased mortality risk associated with weekend admission to hospital (the ‘weekend effect’) has been reported across many health systems. More recently research has focused on causal mechanisms. Variations in the organisation and delivery of in-hospital care between weekends and weekdays have been identified, but this is not always to the detriment of weekend admissions, and the impact on mortality is uncertain. The insights of frontline staff and patients have been neglected. This article reports a qualitative study of patients and clinicians, to explore their views on quality and safety of care at weekends.MethodsWe conducted focus groups and interviews with clinicians and patients with experience of acute medical care, recruited from three UK hospital Trusts. We analysed the data using a thematic analysis approach, aided by the use of NVivo, to explore quality and safety of care at weekends.ResultsWe held four focus groups and completed six in-depth interviews, with 19 clinicians and 12 patients. Four threats to quality and safety were identified as being more prominent at weekends, relating to i) the rescue and stabilisation of sick patients; ii) monitoring and responding to deterioration; iii) timely accurate management of the therapeutic pathway; iv) errors of omission and commission.ConclusionsAt weekends patients and staff are well aware of suboptimal staffing numbers, skill mix and access to resources at weekends, and identify that emergency admissions are prioritised over those already hospitalised. The consequences in terms of quality and safety and patient experience of care are undesirable. Our findings suggest the value of focusing on care processes and systems resilience over the weekends, and how these can be better supported, even in the limited resource environment that exists in many hospitals at weekends.Electronic supplementary materialThe online version of this article (10.1186/s12913-018-3833-z) contains supplementary material, which is available to authorized users.