In this study we aimed to compare the serological markers and ALT levels of patients with hepatitis B infections with HBV DNA levels. A total of 618 serum samples submitted to the laboratory for routine HBV DNA testing were retrospectively included in the study. HBsAg was detected by chemiluminescent method while HbeAg and anti-HBe were detected by macro ELISA method. Quantitative serum HBV DNA levels were detected by Real-Time Polymerase Chain Reaction (PCR) method. In total 305 samples were identified as HBV DNA positive. HBV DNA was determined in 53% of the HBsAg (+) samples, in 84% of the HBeAg (+) samples, in 31% of anti-HBe (+) samples and in 92% of anti-HBc IgM (+) samples. HBV DNA was positive in 12% of the HBsAg (-) and 27% of the HBeAg (-) samples. For the HBV-DNA positive patients, ALT levels were lower than 25 IU/mL in 52% of the patients with HBV DNA <= 10(3)copies/mL, in 26% of the patients with 10(4)-10(6) copies/mL and in 11% of those with HBV DNA >= 10(7) copies/ml. ALT levels were higher than 50 IU/mL in 62% of the patients with HBV DNA >= 10(7) copies/mL. ALT levels higher than normal limits have been observed in most of the patients with high HBV DNA copy numbers, however, no correlation was observed between number of copies and enzyme levels. As a result, widely used serological and biochemical tests, conducted with quantitative HBV DNA detection seems appropriate for the diagnosis of HBV infections.