Introduction: This study examined possible correlations between health information behaviour and illness perception among patients with rare chronic diseases. Illness perception is related to coping strategies used by patients, and some health information behaviour practices may be associated with better coping and more positive perception of illness. Method: Print and online surveys containing questions about health information behaviour and illness perception were conducted in 2013 on a sample representing adult patients suffering from three rare diseases (systemic lupus erythematous, scleroderma and myasthenia gravis) in Croatia. 171 respondents participated in the study. Analysis: Quantitative analyses were carried out on 146 correctly completed questionnaires using the SPSS statistical package. Besides descriptive statistics, Chi-Square tests, T-tests and Kruskal Wallis tests were used to test possible differences between the groups in the sample. Spearman's rank correlation was used for testing statistical dependence between variables. Statistical difference was tested at the level of 95%. Results: Health information seeking was associated with more concern about the illness, but was not associated with personal control over the illness or patients' ability to understand the illness. Using patient organizations as an information source was associated with better understanding of the illness. Avoiding health information was associated with less personal control over the illness and less ability to understand the illness, but no association was found with concern about the illness. Conclusion: This research shows that there are correlations between health information behaviour and beliefs and feelings about the illness, which in turn affect coping strategies and health outcomes. [Note: The publication year (2015) shown on the PDF is incorrect. The correct publication year is 2016.]