BACKGROUND The aim of this study was to assess the influence of socio-demographic and clinical factors on personality trait expression and their relationship with more intense interdialytic disorders and changes in health behaviors of patients with chronic kidney disease (CKD). MATERIAL AND METHODS A total of 200 participants were recruited for the research (84 women and 116 men; aged 61±12 years): 160 patients had CKD stage G4-G5 and 40 healthy participants constituted a control group. A diagnostic poll method was used in the research employing the following questionnaires to collect socio-demographic and clinical data: Health Behavior Inventory (IZZ), Personality Inventory (NEO-FFI), Beck Depression Inventory (BDI), and Researcher's Questionnaire Test. RESULTS Statistically significant differences were found in the intensity of personal traits at different stages of treatment. The influence of factors resulting from CKD on the expression of personality traits increased with subsequent stages of treatment. Depression intensity was not connected with the expression of personality traits. A higher frequency of reported interdialytic disorders was significantly related to a higher degree of openness and conscientiousness and a lower degree of agreeableness. Increased extraversion, conscientiousness, and openness were significantly correlated with more intense health behaviors. CONCLUSIONS Personalities of patients with CKD changed with subsequent stages of treatment and were influenced by socio-demographic and clinical factors. Personalities affected the frequency of reported interdialytic disorders and health behaviors.