Aim: To determine the impact of the Best Practice Spotlight Organization® initiative on nurses' perception of their work environment and their attitudes to evidence-based practice. Design: Quasi-experimental, multicentre study. The intervention is the participation in Best Prectice Spotilight Organizations to implement Best Practice Guidelines. Methods: The study will include seven centres in the interventional group and 10 in the non-equivalent control group, all of them belonging to the Spanish national health system. The Practice Environment Scale of the Nursing Work Index, and the Health Sciences Evidence-Based Practice Questionnaire will be administered to a sample of 1,572 nurses at the beginning of the programme and at 1 year. This 3-year study started in April 2018 and will continue until December 2021. Statistical analyses will be carried out using the SPSS 25.0. This project was approved by the Drug Research Ethics Committee of the Parc de Salut Mar and registered in Clinical Trials. Discussion: The study findings will show the current state of nurses' perception of their work environment and attitudes to evidence-based practice, and possible changes in these parameters due to the programme. Impact: The findings could provide a strong argument for health policymakers to scale up the Best Practice Spotlight Organization® initiative in the Spanish national health system. KEYWORDS: evidence-based practice, implementation, midwives,