Research aim: To explore if socioeconomic status has any influence on the successful preparation of the colon for colonoscopy and successfulness of the whole colonoscopy procedure. Specific aims are: to test if there is a difference between individual groups according to the chronic illness in patients anamnesis and if there is a difference between the groups based on the type of concoction used during the preparation of the colon for the colonoscopy. Subjects and methods: 455 subjects were included in the research, males and females from the Gastroenterology and hepatology institute in Osijek and the Gastroenterology department in Požega. The data were collected from the medical documentation from October 2016. to april 2017. During the documentation inspection the following criteria were taken into account: sex, age, body mass index, marital status, degree of education, place of living, method of preparation for the colonoscopy, chronic diseases and surgical procedures. Results: Colonoscopy was successful most of the times. The most common reason for abandoning the procedure was uncleanliness of the colon mucosa, Age differences found are connected with subjects older than 60 from Požega. The highest number of subjects living in villages and with lower degree of education is found in Požega, while in Osijek, the difference in the degree of education is minimal, and most of the subjects live in the city. Combination of Epsom salt and lavage powder is most commonly used for preparation in Osijek, while in Požega solely Epsom salt is mostly used. Epsom salt is most commonly used with people above the age of 60, with neoplasms and lower degree of education. Conclusion: Socioeconomic factors have partial influence on the preparation of the colon mucosa and the success of the whole colonoscopy procedure. Differences according to sex, age, place of living and chronic diseases were observed.