This paper presents an estimation of local diagnostic reference levels in computed tomography in a large teaching hospital. Local diagnostic reference levels, expressed in terms of volume weighted computed tomography dose index and dose-length product, were estimated for three most frequent adult computer tomography examinations: head, abdomen and pelvis combined, and thorax. The established local diagnostic reference levels values were similar or slightly higher compared to the available guidelines, indicating the possibility for optimization of current practice. Analyzing the protocols used here and recently published studies on dose reduction in computed tomography, a dose-reduction technique, was proposed to decrease tube current values in all three examinations. However, the optimization should be restricted only to standard-sized patients.