Background: Nurse practice environments have well-documented associations with quality of nursing care. Several studies have shown association between high quality to shorter length of stay and lower mortality rates. Objective: To develop an understanding about how nurses at Oslo University Hospital describe their practice environments and how they assess quality of nursing care and patient safety. Furthermore, it was an objective to analyze a possible co-variation between different practice environment factors and relate this to nurse assessed quality of nursing care. In this dissertation, a framework that has systematically implemented evidence-based elements has been used, the American Magnet model. Study participants: The results are collected from the large survey Personal and Patient safety (PePSi), which was distributed to 9548 nurses at 35 Norwegian hospitals during fall of 2009. My study participants were 504 nurses working at medical/surgical wards at Oslo University Hospital. Methods: Cross-sectional, structured survey with an extensive use of a 4-point Likert scale. Analyzes by means of common statistical tests, such as the t-test, ANOVA and Bonferroni. Results: The results from Oslo University Hospital are generally good compared to other Norwegian hospitals, and this is the case on both practice environment and nurse assessed quality of care and patient safety. However, there are quite large variations within OUH, and Rikshospitalet/Radiumhospitalet have generally more positive results, whereas Aker has more negative results on comparison. Nurses report that they are able to fulfill their core tasks at hospitals were they assess the staffing to be sufficient. Conclusion: It is argued that nurses practice environment has a strong co-variation to the nurse assessed quality of care and patient safety, and because of this it is crucial to have systems in place to ensure good practice environments for nurses. With findings from large international studies, it is argue that Norwegian hospitals might use different elements from the Magnet model, even if it is not a goal to achieve Magnet status from the ANCC.