The aim of this article is to provide insight into the current state of nursing care for sleep problems in inpatient and outpatient psychiatric care for adults and the elderly, and to determine if there is any benefit to the implementation of alternative, evidence-based interventions. To research this, the authors carried out a cross-sectional survey by means of a specially developed questionnaire. Between October 2005 and June 2006, 1,181 questionnaires were sent to a sample of nurses working in inpatient and outpatient care for psychiatric patients in five different psychiatric institutions in the Netherlands. Descriptive statistics were used to describe the properties of the sample and its strata. The authors explored differences between subgroups using chi-square, Mann-Whitney or Students t-tests. The authors found that daytime interventions to prevent sleep problems are mostly structural, introducing a structured environment with, for example, set going to bed and getting up times, and stress management activities. Sleep problems during the night are typically approached by observation, environment control and stress management. Experience, knowledge gained by initial training and eminence advice (advice from peers, physicians or experts) are the most frequently used knowledge sources in the care of sleep problems. Nurses were seen to be aware of the importance of sleep and the importance of a good nursing management for sleep problems. However, interventions are rarely evidence-based. Although nurses are satisfied with the care being provided for sleep problems, they are willing to apply alternative evidence-based care. They identified the lack of knowledge, skills and time as obstacles for such implementation.