This is the first study of HCV infection performed in Romania by reverse transcription-polymerase chain reaction (RT-PCR). We set up our own protocol, using "nested" primers located in the 5' UTR of HCV. Thirty two patients, 16 with chronic hepatitis, 7 with hepatic cirrhosis and 9 without chronic hepatic disease were investigated. The assignment of each patient to one of the groups was based on clinical and laboratory criteria, especially transaminase levels and hepatic biopsy findings. In 14 out of 16 (87.5%) chronic hepatitis cases and in 6 cases of hepatic cirrhosis out of 7 (85.7%), there was good agreement between RT-PCR and ELISA results. Transaminase levels were concordant with RT-PCR results in 27 of 29 cases (93.1%) but in only 21 of 29 cases (72.4%) transaminase levels were in agreement with ELISA results. In two patients treated with interferon, transaminase levels and the other clinical and laboratory parameters fell in the normal range in parallel with the disappearance of viremia, whereas anti-HCV antibodies were still detectable. RT-PCR has a higher specificity in detecting the etiology of hepatic diseases if compared to ELISA and an at least equal sensitivity. The method proves to be the best means for the confirmation of HCV infection, and for the monitoring of interferon therapy.