Background/aim: Albumin is the most important protein synthesized by the liver. Posttranscriptional changes occur in the molecular structure of albumin due to various factors and isoforms arise. Ischemic modified albumin (IMA) is one such isoform. This study was conducted to evaluate serum IMA concentrations in patients with hepatitis B virus (HBV)-related chronic liver diseases. Materials and methods: This study included 74 treatment-naive chronic hepatitis B patients, 25 patients with HBV-related cirrhosis, and 49 healthy controls. Serum IMA concentration was measured spectrophotometrically using the albumin cobalt binding test. Results: The mean IMA concentrations in the chronic hepatitis B group and healthy controls were 0.33 ± 0.11 ABSU and 0.27 ± 0.70 ABSU, respectively, and the difference was statistically significant (P < 0.001). Mean IMA/albumin ratios (IMAR) in the chronic hepatitis B and control groups were 0.08 ± 0.04 and 0.06 ± 0.17, respectively, and the difference was also statistically significant (P < 0.001). Higher serum IMA concentrations and IMAR were detected in patients with advanced fibrosis. Conclusion: Serum IMA concentration and IMAR are increased in patients with HBV-related chronic liver diseases and IMA and IMAR are associated with the degree of liver fibrosis. IMA and IMAR may have potential use as noninvasive markers of fibrosis in chronic hepatitis B patients.