Objectives: Adrenal masses are more frequently detected in autopsy series in recent years and are more frequently detected in clinical practice due to the development of radiological examinations. After the detection of an adrenal mass, the first two important questions come to mind. Does the mass hormonally active (functionally) or not active (non-functional), and this mass is a benign formation or is it malignant? The answer to these two questions is the obligatory questions that clinicians must answer in order to make an operation decision. The decision of operation in non-functioning adrenal masses is directly proportional to the mass's neoplastic potential. If a preoperative histopathological diagnosis is not available; this potential is predicted by the size of the mass in radiological imaging. It is shown that the malignancy rate in adrenal masses is higher in lesions 6 cm and above. In this study, we aimed to determine whether the rate of malignancy is really high in histopathological examination as a result of adrenalectomy operations performed in our clinic between the years of 2010-2012.Methods: Fourteen women and 4 men with 6 cm or higher adrenal masses patients which performed adrenalectomy by Eskişehir Osmangazi University Faculty of Medicine Department of General Surgery between 2010-2012 were included in this study. The results of the final histopathological analysis were classified retrospectively. Results: The rate of malignancy in adrenal masses of 6 cm or more supported by the literature was found to be high in our clinical series. Conclusions: As a result of our clinical retrospective study, we think that the extent of the formation in the related gland is highly effective and significant in making an operation decision before adrenalectomy.