©Cukurova University, Faculty of Medicine. All rights reserved.Objective: The fact that breast cancer is a common type of cancer necessitates the research on the risk factors of it. Studies about type C personality, which is stated to be a risk factor for breast cancer, yielded controversial results regarding type C personality-cancer development relationship. Type C personality has two factors, namely self sacrificing behavior and emotional non-expressiveness. To measure type C personality traits in Turkish breast cancer patients, adaptation of Type C Behavior-TCB Scale and examination of its reliability and validity were necessary. Methods: One hundred and one Turkish breast cancer patients and a control group which consisted of 99 participants, who were not cancer patients, received Type C Personality Scale, Toronto Alexithymia Scale, and extraversion subscale of Basic Personality Traits Inventory. One month after the first application, Type C Personality Scale was readministrated to measure test-retest reliability of the scale. Findings: Factor analysis confirmed the exact fit of the two-factor model. While the internal consistency reliability of the whole scale was 0.81, test retest reliability of the whole scale was 0.87. The internal consistency reliabilities of subscales were ranged between 0.80 and 0.86. In order to test divergent validity of the scale, extraversion subscale of the Basic Personality Traits Inventory (r=-0.24, p<0.05), and to test convergent validity of the scale, Toronto Alexithymia Scale (r=0.52, p<0.01) were used. Discussion: The results of the study indicate that Turkish adaptation of the Type C Personality Scale has satisfactory reliability and validity values.