Detection of cancer is often equal to facing with a crisis by the patients. Traditionally it is believed that cancer diagnosis should not be told to the patients. The aim of this study was to compare the attitudes towards the disclosure of cancer diagnosis in patients with cancer and control group included healthy people. This crosssectional study was carried out in 2015 with a total of 531 people. We used three questionnaires to collect data. The first one was EORTC QLQ-C30 to assess quality of life of patients with cancer. The second one included items to assess the patients' willingness for detection of the cancer diagnosis. Finally, the third one was the DUREL to evaluate religiosity. Five hundred and thirty one subjects including 216 patients with cancer and 315 healthy people were studied. Mean age of participants was 44 ± 15.7, 50.5% were female. Overall, 63% of patients with cancer were informed of their disease status and 37% uninformed. A significant association was seen between the awareness of cancer with physical and social functioning of quality of life. There was a positive significant association between the tendency for being informed of the diagnosis and non-organizational religious activity in participants without cancer. Global health status and all dimensions of religious were correlated in patients significantly. We found the majority of subjects tend to be aware of the disclosure of diagnosis. The physical and social functioning of quality of life were better in uninformed patients than informed patients.