BACKGROUND The aim of this study was to analyze the psychological aspects of patients during their orthodontic treatment, evaluating their expectations during treatment comparing Greek patients to Italian patients. METHODS This cross sectional descriptive study involved a sample of 228 patients (113 Italians -115 Greeks) undergoing fixed or removable orthodontic treatment. A questionnaire comprising of six questions was used and patients scored each question on a 0-10 Scale. Participants completed a validated questionnaire measure of orthodontic expectations that was tested for reliability. Descriptive analysis of the responses was undertaken, and comparisons between boys and girls, as well as between Greek and Italian patients, was made. The expectation score was calculated by summarizing the 6 items (A1 to A6). Reliability Analysis was performed using the Item-test, Item-rest correlation and the Cronbach's α. Items with a Cronbach's α coefficients greater than 0.7 are considered acceptable. To investigate the effect of the City and Gender on the expectation score, an univariate analysis was carried out by the Wilcoxon Rank Sum Test. Differences, with a P value less than 0.05, were selected as significant. RESULTS Overall expectation Cronbach's α coefficient (internal consistency) was 0.73 (95% CI: 0.64-0.81). The mean of expectation items was 7.8 (SD=1.8). A significant slight correlation was found between motivation (item A1) and main reason of treatment (item A3) (r=0.17; P=0.0122). Moreover, there was a significant moderate correlation between compliance (item A4) and expectation (item A6) (r=0. 58; P<0.0001). CONCLUSIONS Male showed a significant higher overall score compared to female sample, as well as Greek patients compared to Italians.