Entrance doors at wards where psychiatric care is provided are sometimes locked, which is not the case at wards where somatic care is provided. How locked entrance doors at psychiatric wards are experienced by patients has been investigated to a very limited extent. The aim was to describe voluntarily admitted patients' perceptions of advantages and disadvantages about being cared for on a psychiatric ward with a locked entrance door. Audio-taped, semi-structured interviews were conducted with 20 patients voluntarily admitted at psychiatric wards. Content analysis revealed six categories of advantages and 11 categories of disadvantages. Most advantages were categorized as "protects patients and staff against 'the outside' ", "provides patients with a secure and efficient care" and "provides staff with a sense of control over the patients". Most disadvantages were categorized as "makes patients feel confined", "makes patients feel dependent on the staff" and "makes patients feel worse emotionally". Patients perceive a variety of advantages and disadvantages, for themselves, their visitors and staff, connected to locked entrance doors at psychiatric wards. A locked door may make the ward appear as both a prison and a sanctuary. It is important that staff try to minimize patients' concerns connected to the locked door.