Type D personality is susceptible for concern, tension, unhappiness and dark and negative view to the life. They easily get angry and in general experience less positive emotions, and this status may create problems in the process of therapy of chronic diseases or add difficulties thereto. This research aims to investigate the share of personality type elements (negative emotion and social inhibition) in disease perception of cancer patients. For this purpose, in a descriptive study of correlation type, 176 cancer patients of Shohadaye Tajrish and Imam Hospitals were selected as convenience sample and were assessed with regards to psychological traits, D type personality and attitude to therapy. The results of regression analysis of points indicated that high D type personality, negative emotion and social inhibition are associated with disease perception, and its subtests including consequences, timeline, personal control, disease control, identity, concern, disease understanding and emotional representation. Regression analysis indicated that the points of type D personality justify 71% of variance of disease perception points. Accordingly, whatever D type personality in them is higher, they have worse perception of their disease and its related aspects. Therefore, the effect of high D type personality should be taken into consideration in continue of treatment process of cancer patients.