Portal vein thrombosis (PVT) seems rare among HIV infected patients. Even though, the report of such cases is of great interest because it may help to determine the factors of occurrence. We describe cases of PVT in 4 HIV-infected men, aged 32 - 64. Two of them were co-infected with hepatitis C virus (HCV). The four patients had a history of disseminated mycobacterial infection (one case of tuberculosis, 3 cases of mycobacterium avium complex infection) with abdominal lymphadenitis. Despite HAART, their immunodeficiency was profound (CD4: 65 to 216/mm(3)). At the time of diagnosis, two patients were treated with protease-inhibitor containing regimen: indinavir (one case), ritonavir-saquinavir (one case). PVT was revealed by haematemesis (one case), abdominal pain (ome case), anasarca (2 cases). In three patients, the diagnosis of PVT was confirmed by imagery (echo-doppler or angio- RMI), and for the last patient, PVT was found during the transjugular intrahepatic portosystemic shunt setup. A low level of C protein was diagnosed in one case. Cirrhosis was not found in HIV-HCV co-infected patients. Two patients died early after diagnosis, one patient died 3 years after the onset of symptoms. Various factors may cause the development of a PVT in HIV infected patient. Serious immunodeficiency, opportunistic infections such as tuberculosis and mycobacterium avium complex related infection with abdominal lymphadenitis can further the development of PVT. Protease-inhibitor might have facilitated the process. Due to the severe prognosis of advanced cases, early evocation of diagnosis is needed.