Objectives To explore in-patients’ experiences being a fellow patient to patients who become critically ill. Design The study was designed as a qualitative phenomenological study. Setting The study was conducted in a surgical ward of a hospital in Denmark. Subjects Fifteen fellow patients to patients, who became critically ill. Results Three key themes emerged from the analysis of the data: patients’ interaction, anxiety, and professional support. These findings demonstrated the importance of understanding how patients experienced being a fellow patient to patients, who become critically ill, their views on interacting with such a patient, how the patients who become critically ill influenced them, and what kind of support they needed from the health professionals. Conclusion The findings highlighted the different emotions and feelings experienced by fellow patients. It showed how the impact of the situation can lead to anxiety, a feeling of being forced into patient inter-action and the lack of professional support. Health professionals should have a central role in supporting the fellow patients and communicating with them about their experiences and this does not seem to be fulfilled sufficiently in daily clinical practice.