The purpose of the study was to assess the patient’s attitude towards the use of a rubber dam and to determine whether any clinical factors influence it. After receiving endodontic treatment under a rubber dam, patients were asked to complete an anonymous questionnaire. They were divided into 2 groups: Group 1 - operators were final-year dental students at the School of Dental Medicine University of Zagreb and Group 2 - operators were (dentists) dental specialists and resident dentists at the Department of Restorative Dentistry and Endodontics, School of Dental Medicine University of Zagreb. The data were statistically analysed by descriptive statistics and Pearson chi square and variance analysis. The majority of the patients (69.1%) in both groups would prefer rubber dam use at their next appointment and consider it pleasant and comfortable to wear (58.2%). Dentists did not explain the reason for the use of the rubber dam to 40.0% of the patients, but when they did, all but two patients understood the explanation. The time required for placing the rubber dam without the assistant’s help was 3 minutes on average and the duration of the endodontic treatment under rubber dam was 69 minutes on average. When compared to the dental specialists students required more time to place the rubber dam and to perform endodontic treatment under it. From this study it can be concluded that patients do not have a negative attitude towards the use of a rubber dam, that the placement of a rubber dam does not take long and that operator’s experience influences the patient’s attitude.