Objective: Aims of this study are to compare the alexithymia scores of patients with unipolar depression (UD), bipolar affective disorder depressive episode (BAD-D) and healthy controls, to explore the effects of alexithymia scores on both severity of depression symptoms and quality of life. Methods: Case group of the study is consisted of one hundred and eighteen UD diagnosed, forty eight BAD-depression diagnosed patients, based on DSM-IV-TR criteria. Control group of the study is consisted of ninety six people who had no history of psychiatric disease. Overall, 262 people had involved in the study. Sociodemographic and Clinical Data Form, Hamilton Rating Scale for Depression (HRDS), Beck Depression Inventory (BDI), Toronto Alexithymia Scale (TAS-20) and SF-36 Quality of Life Scale are used for acquiring information of the patients. Results: Mean of age, gender, marital status, place for living, level of income of UD, BAD-D and control groups were similar. Statistically significant differences were observed in between UD, BAD-D and control groups, in terms of HRDS, TAS-20 and SF-36 scores. Mean group scores of UD and BAD-D group were higher than controls, in terms of all scales. However, mean points of UD and BAD-D groups were similar in terms of four scales. Patients with UD and BAD-D had positive relationship with TAS-20, BRDS and BDI; negative relationship between SF-36, significantly. In conclusion, it is found that alexithymia scores of UD and BAD-D groups were higher; quality of life scores were lower than controls. It is also observed that patients with higher alexithymia scores have more severe depressive symptoms and having a less sense of quality of life. Although our findings indicate that presense of alexithymia is important in depressive disorders, however no difference were found between alexithymia scores in patients with UD and BAD-D. Discussion: Alexithymia scores of all groups had positively related with depression, negatively related with quality of life. Our findings showed that, alexithymia is an important factor to the diagnosis of depressive disorders, however alexithymia is not a marker to make differential diagnosis of BAD-D and UD.