Liver progenitor cells, thought to reside in the terminal bile ductules (canals of Hering) at the interface between portal tracts and liver lobule, proliferate during severe hepatic injury. They may contribute to hepatocyte regeneration, or even take over this role if the liver injury is severe and associated with an impairment of hepatocyte proliferation. They represent promising targets in an attempt to stimulate liver regeneration in chronic diseases. Recent studies on liver progenitor cell recruitment in response to injury in chronic viral hepatitis B, hepatitis C, alcoholic and non-alcoholic liver diseases are presented in this review, as well as clinical trials in which stem cells are administered as a therapeutic intervention to promote liver regeneration. Liver progenitor cell expansion is part of the disease process itself and may contribute to disease severity, mainly related to fibrosis. As the majority of these progenitor cells tend to acquire a biliary phenotype, their role in liver repair and improvement in liver function remains to be addressed. Present data on stem cell therapy are heterogeneous in terms of methods and endpoints; thus, results need to be carefully examined prior to drawing a conclusion on possible benefits.