Background: The overall purpose of diaries written during an intensive care stay is to help patients fill in memory gaps from the illness trajectory, which might promote long-term psychological recovery. Diaries have also been shown to benefit nurses in maintaining a view of the patient as a person in the highly technical environment and to promote reflection. There is a lack of research on how nurses might be affected by writing a diary for critically ill patients with a poor prognosis. Objectives: The aim of this study was to investigate nurses' experience of writing diaries for intensive care patients with a poor prognosis. Methods: This study has a qualitative descriptive design and was inspired by the methodology of interpretive description. Twenty-three nurses from three Norwegian hospitals with a well-established practice of writing diaries participated in four focus groups. Reflexive thematic analysis was used. The study was reported according to the Consolidated Criteria for Reporting Qualitative Research checklist. Findings: The overarching theme resulting from our analysis was “Finding the right words”. This theme represents the challenge of writing in view of the uncertainty of the patient's survival and of who would read the diary. It was important to strike the right tone with these uncertainties in mind. When the patient's life could not be saved, the purpose of the diary expanded to comforting the family. To put an extra effort into making the diary something special when the patient was dying was also a meaningful activity for the nurses. Conclusions: Diaries may serve other purposes than helping patients to understand their critical illness trajectory. In cases of a poor prognosis, nurses adapted their writing to comfort the family rather than informing the patient. Diary writing was meaningful for the nurses in managing care of the dying patient.