Background: We investigated the impact of financial compensation on patients' decision of participation in clinical trials and the related factors with patients' attitudes and considerations. Methods: A survey questionnaire was placed from October 31 to November 16, 2017 to the subjects who were enrolled in the trials of chronic diseases. Patients' socio-demographic characteristics were collected and the potential reasons for participating in the trials were assessed using 5-likert scores. Results: Sixty eight of 110 respondents (61.8%) indicated to participate clinical trials regardless of financial compensation. The differences were found between patients who were unwilling to participate without compensation and those who were willing to participate regardless of compensation in mean ages (43.9 years vs. 52.0 years, p<0.05), marital status (married, 47.6% vs 79.4%, p<0.01), religions (yes, 45.2% vs 67.6%, p<0.05) and monthly income (${\geq}3$ million won, 19.0% vs 45.6%, p<0.01). The potential reasons for participation in the trials between two groups were doctor's suggestion (52.4% vs. 77.9%, p<0.01), the expectation of health improvement (54.8% vs. 73.5%, p<0.05), the types and numbers of procedure (33.3% vs. 16.2%, p<0.05) and the duration of clinical trials (59.5% vs. 27.9%, p=0.001). In regression analysis, the monthly income of ${\geq}3$ million won (odd ratio, OR=3.221, p=0.026,) and the duration of trials (OR=0.290, p=0.017) were related to the group with the willingness to participate regardless of compensation. Conclusion: This stady showed that more than half of study subjects would participate in the clinical trials of chronic diseases regardless of financial compensation.