Most liver diseases for which liver transplantation is performed recur after liver transplantation. The clinical impact of recurrence varies. For autoimmune liver diseases, such as primary biliary cirrhosis, primary sclerosing cholangitis, and autoimmune hepatitis, clinically significant recurrence appears to be relatively rare. Whether these diseases recur in any meaningful way after liver transplantation is still controversial. For the chronic viral diseases, hepatitis B and C, the issue is not whether they recur--they clearly do--but whether the recurrence affects prognosis and how best to manage recurrent disease. For hepatitis B virus (HBV), reinfection can lead to accelerated liver injury, graft loss, and dramatically worse patient and graft survival rates, whereas the prognosis of recurrent hepatitis C virus (HCV), at least in the short-term, appears to be more benign. Major advances have been made in preventing liver allograft reinfection with HBV. Before these advances, chronic hepatitis B was considered a relative contraindication to liver transplantation because the allografts almost always became reinfected. With the current strategies for preventing HBV reinfection, however, the graft and patient survival rates after transplantation for chronic hepatitis B approach those for nonviral diseases. The development of resistance to antiviral therapy is likely to represent the major problem in the future and mandate the use of combination therapy. There is currently no effective therapy available for recurrent hepatitis C. Until such therapy is developed, recurrent hepatitis C remains the most challenging problem facing liver transplant physicians and surgeons.