Background: The implementation of evidence-based methods in hospital settings is challenging and multifaceted. There are several different factors that may affect implementation processes, of which the organisational culture may be one. It is well known that conservative organisational culture can hinder implementations; accordingly, a mix of different organisational cultures is preferable. Aim: The aim of this thesis was to follow the implementation process of an ICF-based assessment tool regarding cultural differences associated with the implementation in a psychiatric clinic. As part of the project, an assessment tool based on the International classifi cation of functioning disability and health (ICF) was developed and implemented. Method: In Study I, three Swedish expert groups participated and analysis of inter-rater reliability was conducted through simulated patient cases. In Study II, data were collected through focus group interviews pre- and post-implementation of the ICF-based assessment tool; thereafter, data were analysed using directed content analysis guided by Normalization Process Theory (NPT). Data from 109 nursing staff who completed the organisational values questionnaire (OVQ) and resistance to change (RTC) were investigated, and the association between the OVQ and RTC was examined with regression analysis (Study III). Patients n=50 representing the intervention hospital and n=64 representing the control hospital answered the Empowerment scale (ES) and Quality in psychiatric care (QPC-IP) (n=45 from intervention hospital and n=64 from control hospital). Staff n=37 at the control hospital answered the OVQ which was presented as descriptive data (Study IV). Results: Inter-rater reliability of the ICF-based assessment tool (DLDA) displayed acceptable kappa values (Study I). The DLDA tool showed the potential for empowering patients. Furthermore, it was considered useful for dialogues, refl ection and for identifying patients’ strengths. Nonetheless, it was diffi cult to implement it in practice due to contributing factors such as time pressure, heavy workload, stress and lack of routine in using the tool (Study II). The intervention hospital was characterised by an organisational culture of trust, belongingness and fl exibility, i.e. a human relation culture. One ward (I.W.3), however, was not dominated by a human relation culture. This ward had an almost equal mix of different cultures (human relation, open system, internal processes and rational goal) (Study III). The results of Study IV were non-signifi cant; however, it indicated that intervention ward 3 proved to be the most prominent ward regarding patient participation and empowerment among the intervention group. The results suggest hospital wards with equal mix of different cultures is more successful than cultural polarisation. Conclusion: Only one of fi ve wards succeeded in implementing the DLDA successfully (ward 5). Ward number three was the most successful of the inpatient intervention wards. The intent of the DLDA method was considered to be good and its use in a psychiatric nursing context can provide structured support in order to improve the dialogue with the patient, but it was not used in practice in all the studied wards. The organisational culture of the intervention hospital was dominated by human relation properties, however with one exception, ward number three. The results tentatively show that organisational culture may affect outcomes of implementation processes. Consequently, it appears that an equal mix of different cultures are more auspicious than cultural polarisations. The results seems to confi rm previous research, where one ward with a balanced mix of different cultures succeeded best to implement DLDA, of the wards representing psychiatric inpatient care. Ward number three did also show the best results in terms of empowerment and patient participation of the intervention wards. Further research aims to continue developing and conducting psychometric testing of the DLDA tool. The DLDAs impact on patient assessed empowerment and patient participation requires studies on larger populations than the current study