Knowledge of health care professionals’ different understandings of diabetes care is important when preparing such professionals in patient education. For patients to manage illness effectively, the actions of health care professionals are crucial. Patients’ understanding of their condition should be taken as the point of departure when creating a learning situation. The professionals’ understandings of diabetes care were mapped using a survey including 169 primary care doctors, nurses, assistant nurses and chiropodists in Stockholm, Sweden. The responses were analysed using a phenomenographic approach. Five understandings were identified: the professionals treat the patients, the professionals give information, the professionals focus relation and organisation, the professionals seek the patient’s agreement, and the professionals focus the patient’s understanding of the situation. Only 20 (12%) of the 169 professional caregivers focused the patient’s understanding. Professionals need to develop their understandings of health care and the professional–patient interaction in order to support the patients’ learning.