Liver regeneration has traditionally been investigated in mammalian models. Recent technological developments in mouse genetics have greatly enhanced the resolving power of these studies. In addition, the zebrafish system has emerged as a complementary genetic system to study liver regeneration. One of the most promising attributes of the zebrafish system is its amenability to large-scale screens including genetic and chemical screens. Also, as our understanding of liver development is becoming more detailed, it is important to evaluate the commonalities and differences between organ development and regeneration.