This qualitative study investigates through a realist evaluation how the work training programme of 10 community health workers (CHWs) contributed to culturally competent home care services. A European Social Fund project trained 10 jobseekers with migration backgrounds to become CHWs in Brussels (Belgium). Three research questions were formulated: (a) What increase in the cultural competence of the home care organisations can be identified at the end of the project? (b) How did the training contribute to this increase? (c) Which factors and preconditions made the positive outcomes of the training more likely? This study analysed 10 mid-term interviews with individual CHWs in training and four focus groups at the end of the project with CHWs, care employees, trainers and project coordinators (N = 25). First, the results showed that the increase in cultural competence was located mostly on the surface structure of the organisation (e.g. adapting communication materials) and not in its deeper structure. Second, the principles of strengths-based education proved to be important during the training (e.g. getting to know, recognise and address the competences and skills of the CHWs). Third, contextual factors at the micro-level (e.g. interest in care and cultures), the exo-level (e.g. management culture) and the macro-level (e.g. policy regulations) could foster or hinder the process of increasing cultural competence. This paper concludes that although the project contributed to a shift in organisational culture towards cultural competence, it remains challenging to effect a similar shift in the deep structure of care organisations.