Background: Cirrhosis is one of the most severe liver complications, with multiple etiologies. The torque teno virus (TTV), also known as transfusion transmitted virus, which has a high incidence in the world population, is one of the possible increasing risk factors in patients with idiopathic fulminant hepatitis and cryptogenic cirrhosis.Objectives: The aim of this study was to evaluate solitary and co-infection with TTV, in patients with cryptogenic and determined cause of cirrhosis.Patients and Methods: In this cross-sectional study, 200 liver transplant patients were consecutively recruited between years 2007 and 2011. Patients were classified, based on recognition of the etiology of cirrhosis to determined (n = 81) and cryptogenic (n = 119) patient groups. The existence of TTV infection was analyzed, using a semi-nested polymerase chain reaction method. The presence of hepatitis B virus (HBV) infective markers, including HBV DNA, hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis B core antibody (HBcAb), and hepatitis B e antibody (HBeAb), was evaluated using qualitative polymerase chain reaction and enzyme linked immunosorbent assay protocols, respectively.Results: The TTV infection was found in 37 of 200 (18.5%) and 53 of 200 (26.5%) plasma and tissue samples of studied liver transplanted patients, respectively. The TTV genomic DNA was found in 32 (26.9%) and 28 (23.5%) of 119 liver tissue and plasma samples of transplanted patients with cryptogenic cirrhosis, respectively. The genomic DNA of TTV was also diagnosed in 21 (25.9%) and nine (11.1%) of the 81 liver tissue and plasma samples of patients with determined cirrhosis, respectively. Significant associations were found between TTV infection with HBV molecular and immunologic infective markers, in liver transplanted patients, with determined and cryptogenic cirrhosis.Conclusions: The diagnosis of the high frequency of solitary TTV and co-infection with HBV, in both liver transplanted patients with cryptogenic and determined cirrhosis, emphasized on the importance of TTV infection in the development of cirrhosis, especially in the cases of cryptogenic ones, prompting for further studies the confirm this agent in the etiology of determined cirrhosis.