Adenocarcinoma is the most frequent pathology diagnosed in patients with pancreatic mass lesions, and it must be differentiated into benign and inflammatory tumors.The aim of the study was to define the efficacy of ultrasound, computed tomography (US/CT) and fine-needle aspiration biopsy (FNAB) in the assessment of pancreatic mass lesions.Material and methods. The study population comprised 150 consecutive patients with heterogeneous pancreatic mass lesions treated at our department between 1999 and 2004. Imaging examinations with US/CT and FNAB were carried out in all the patients. The final nature of the tumor was established based on histopathology in patients who underwent surgery or based on the follow-up course in patients who were not referred to surgical exploration. The sensitivity and specificity of US/CT and FNAB were calculated by comparing the clinical diagnosis resulting from US/CT interpretation and FNAB results obtained before treatment with the final diagnosis.Results. FNAB appeared to be a safe and relatively simple procedure with no remarkable complications. Malignant tumors were finally diagnosed in 99 (66%), and benign were finally diagnosed tumors in 51 (34%) patients. The sensitivity and specificity were calculated to be 90% and 77.3% for US/CT and 86.9% and 100% for FNAB, respectively.Conclusions. The imaging examination with US/CT is a relatively reliable method for the differential diagnosis of pancreatic mass lesions. A positive FNAB has still remained the most accurate diagnostic method.