Dispersion of rat liver tissue by perfusion with collagenase and hyaluronidase was maximally stimulated by Ca 2+ at 5 mM concentration. Mg 2+ and Zn 2+ inhibited enzymatic dispersion, while Co 2+, K +, SO 4 2− and HPO 4 2− were without effect. Dispersion was optimal at pH 7.5. Enzymatic dispersion was more effective if cellular adhesion was first reduced by the removal of Ca 2+. This could be accomplished by pre-perfusing the liver at a high rate with Ca 2+-free medium. Chelating agents like ethyleneglycol- bis (β-aminoethyl ether) N,N′-tetraacetic acid (EGTA) and ethylenediamine tetraacetic acid (EDTA) had no further effect under these conditions. Cellular adhesion was specifically dependent on Ca 2+, and was not maintained if Ca 2+ was replaced by Mg 2+. The presence of K + appeared to reduce cellular adhesion, and the removal of K + by pre-perfusion and tetraphenyl boron (TPB) treatment did not favour dispersion.