Objective: To evaluate a strategy for supporting nurses to work with quality improvement (QI). Design: Post-intervention evaluation. Study participants and intervention: 240 nurses participated in a uniformly designed 4 day basic training course in applying a model for QI. Of these, 156 nurses from over 50 healthcare institutions constituted the generic education (GE) group while 84 nurses from 42 neonatal units took part in a project to develop national guidelines, constituting the targeted intervention (TI) group. Method: Postal questionnaire 4 years after the training courses. Results: The response rate was 80% in the TI group and 64% in the GE group. Nurses in the TI group had a significantly higher rate in completing all phases of the QI cycle (p=O.O002). With no differences between the groups, 39% of ali nurses were still involved in QI work 4 years after the training courses. Three factors were significantly related to nurses continuing their involvement in QI projects: remaining employed on the same unit (OR 11.3), taking courses in nursing science (OR 4.1), and maintenance of the same QI model (OR 3.1). Reported motives for remaining active in QI work were the enhancement of knowledge, influence over clinical practice, and development as a nurse. Reasons for discontinuation were organisational restructuring, a lack of facilitation and knowledge, and change of workplace. Conclusions: Participation in a national guideline project, including a common focus for improvement, facilitation and opportunities for networking, seems to have enhanced the ability to carry out the process of QI, but not to sustain the QI work over a longer period.