Isolation of preneoplastic cell populations would greatly facilitate analysis of the development of liver carcinogenesis. Suspensions of intact single cells can be prepared in an almost quantitative yield by two‐step perfusion of the isolated liver. In the first step the liver is perfused with a Ca2+‐free buffer (or with EGTA) in order to irreversibly cleave the desmosomes; in the second step perfusion with Ca2+‐activated collagenase dissolves the collagenous extracellular matrix.