Aim of the study: The aim of this study was to determine the awareness of patients about the importance of conducting oral hygiene of mobile dentures and the success in performing it. Draft study: Cross-sectional survey conducted in the area of the city of Osijek. Respondents and methods: The study included 60 subjects aged 40 to 90 with mobile prosthetic dentures. The research was carried out in Osijek-Baranja County in the period from June to August 2022 inside the dental office within the Health Center of the Osijek Baranja County. An individual survey questionnaire of 17 multiple-answer questions was created for the research. An intraoral examination of the patient was also carried out. Results: The survey was conducted on 60 subjects, of whom 77% were women and 23% were men. 52% of subjects reported constantly or occasionally wearing prosthesis during the night, with as many as 74% stating that they had some type of oral disease related to the prosthesis. In the most cases, the dentist was the person who gave the instructions of how to clean the prosthesis. The most common method of cleaning was a brush and toothpaste in combination with denture cleaners. According to the age, gender, socioeconomic status, methods and frequency in cleaning, the habit of removing the prosthesis before bedtime, the type of substitute and the degree of purity, a significant difference was not found according to the assessment of successful oral hygiene. Conclusion: In the future, it is advisable to make additions to the cohort study with a larger number of subjects in the area of Osijek-Baranja County and the Republic of Croatia. This study highlights the importance of educating patients with dentures in order to improve oral hygiene of the oral cavity and prosthesis.