1.Cryopreservation of precision-cut tissue slices (PCTS) would have many advantages for drug development and would encourage more extensive use of the PCTS preparation. 2.Three methods have been studied to date: slow freezing, fast freezing, and vitrification. 3.Slow freezing can be very effective for some PCTS but is devastating to rat liver PCTS. Fast freezing can be successful for rat liver PCTS but is devastating to renal PCTS and has given inconsistent results even for rat liver PCTS. Vitrification has been effective for some slice systems but less effective for rat liver PCTS. Rat liver PCTS appear to be particularly difficult to cryopreserve well. 4.The general cryobiological principles of slow freezing, rapid freezing, and vitrification are reviewed. The empirical literature on the cryopreservation of PCTS has not taken sufficient account of these principles, and may, for example, include the effects of easily preventable osmotic injury. 5.More attention is needed to the effects of cryopreservation on specific cell types within PCTS and to the general integrity and viability of cryopreserved PCTS. Drug metabolism as a sole endpoint of study can be highly misleading. 6.Better application of cryobiological principles may enable improved results in the future.