Fever of unknown origin (FUO) is a diagnostic challenge for the practising physician. Detailed medical history, physical examination, non-invasive laboratory tests, and radiologic examinations compose the first level in the diagnostic approach to the FUO. When a diagnosis cannot be established with these procedures, some invasive diagnostic techniques and finally exploratory laparotomy are performed. Although advanced diagnostic measures and imaging-guided less invasive procedures have decreased the need, laparotomy remains as a final diagnostic method for FUO cases. In this study we evaluate the role and importance of laparotomy in the diagnosis of our FUO cases.