Background: The causes of cryptogenic cirrhosis, as one of the most important unresolved issues in the management of liver failure, remains unknown. Hepatitis B virus (HBV) infection with a high impact in Iranian liver graft recipients may have a key role in introducing and developing cryptogenic cirrhosis, especially in the occult form. Therefore, the prevalence of occult HBV infection was evaluated in liver transplant recipients with cryptogenic cirrhosis. Methods: In this cross-sectional study, a total of 127 liver transplant recipients with cryptogenic cirrhosis were recruited. The serum samples of patients were evaluated for immunological HBV infective markers, using enzyme-linked immune sorbent assay (ELISA) methods. Moreover, immunohistochemistry (IHC) was used for detection of HBsAg in liver tissue sections. Collected serums and liver tissue samples were also examined for HBV genomic DNA, using a qualitative polymerase chain reaction (PCR) technique. Results: HBsAg was not found in any studied liver tissue or serum samples. However, HBV genomic DNA was found in the liver tissue and serum samples of 35.4% and 36.2% of the liver transplant patients with cryptogenic cirrhosis, respectively. Occult HBV infection was found in 35.4% of the patients with cryptogenic cirrhosis. Seropositive and seronegative types of occult HBV infection were found in 82.2% and 17.8% of the patients, respectively. Conclusions: Findings of the high prevalence of molecular and immunological markers of HBV infection, especially occult ones, in liver transplanted patients with cryptogenic cirrhosis was re-enforced. These results indicate the important role of occult HBV infection in the pathogenesis of cryptogenic cirrhosis, which needs to be evaluated in the future through comprehensive studies.