Adrenal mass discovered during imaging for non-adrenal related causes is called incidentaloma. Adrenal masses can be asymptomatic or can have clinical manifestations related to hormone overproduction. The increasing number of discovered adrenal mass is by no doubt due to quick development of radiology procedures. The aim of study was determination of statistical frequency of different types of adrenal tumours and related clinical symptoms based on retrospective analysis of patients diagnosed in the Department of Endocrinology, Collegium Medicum, Jagiellonian University. There were 271 patients (184 female, 87 male) with incidentaloma confirmed in CT scan from January 2000 to June 2005. Mean patients' age was 56.8 +/- 12.7 years. The most common localisation was right adrenal gland (135 cases), bilaterally in 29 patients. Tumours less than 3 cm in diameter were observed in 58.5% of diagnosed persons, tumours from 3 to 6 cm in 33.3% of cases and tumours bigger than 6 cm in 8.2% patients. Hormone excess associated with adrenal mass was detected in 37 (13.6%) patients. Pheochromocytoma was diagnosed in 20 patients (7.4%). Subclinical hypercortisolism was found in 13 patients (4.8%). Primary hyperaldosteronism was diagnosed in 4 cases (1,4%). In patients with adrenal mass incidentaloma hormone tests should be performed before making therapeutic decisions despite no clinical symptoms.