The degree of accuracy with which physicians understand their patients' views may be of central importance for promoting self-care in the majority of chronic illnesses and in type 2 diabetes in particular. The objectives of this study were to measure the accuracy of the general practitioners' understanding of the patients' views and relate it to health behavioural outcomes in patients with non-complicated type 2 diabetes. The participants in this cross-sectional study consisted of 14 clinicians and 78 of their patients from Paris, France. The predictors were levels of accuracy in understanding the patients' views derived from the illness perception questionnaire-revised (IPQ-R). The outcomes were patient-reported self-care measures. In regression models controlling for clinical and personal variables, higher accuracy on chronicity beliefs was associated with an improved diet and increased blood glucose self-testing and higher accuracy in identifying treatment control beliefs was associated with better dietary self-care. Accuracy was higher with regard to beliefs about causes, treatment control and consequences. These results suggest that accuracy may impact self-care in specific domains of illness perception but not others. The results may help identify useful avenues of communication training designed for professionals.