Patients' health and health needs are influenced by categories of difference like sex, gender, ethnic origin and socioeconomic status (SES). To enhance awareness of this diversity among patients and to provide holistic care for them, health professionals should first be aware of the relation between dimensions of diversity and patients' health and health demands. This paper presents a formative process evaluation of a diversity sensitivity training programme for healthcare professionals. The training was implemented in three healthcare settings (mental healthcare, nursing home and hospital care). Mixed methods were used to monitor the implementation of the training and its effects after three years. Findings demonstrate that the training stimulated participants' awareness, knowledge and critical attitudes towards diversity. Their motivation and willingness to take action regarding diversity was also enhanced. Yet these developments were less apparent among nursing home participants who felt less satisfied and did not develop a critical perspective on this issue. Qualitative data were helpful to explain differences between the settings. By means of the combination of quantitative and qualitative data, we can conclude that individual learning was not enough to guarantee a sensitive approach to diversity at the organizational level. (Contains 6 tables and 2 figures.)