Multiple forms of microsomal and plasma membrane sialyl and fucosyltransferases from chicken liver and transplantable hepatoma Mc-29 have been separated by means of isoelectric focusing. A net different pattern was distinguished between liver and hepatoma microsomal and plasma-membrane associated transferases. Microsomal sialyltransferase from hepatoma Mc-29 has typical forms with pI = 5.69, 7.43, 8.05 and 8.56, while in plasma membrane, enzymes with pI = 5.00 and 8.70 occur. The presence of 9 forms of fucosyltransferase within the pH range 3.46-9.57 for hepatoma microsomes and within pH 4.52-9.60 for plasma membranes was detected. Forms with pI 5.10, 5.75 and 7.87 could be considered specific for the hepatoma microsomal enzyme, and forms with pI 4.52, 4.85 and 5.20 for the plasma-membrane associated enzyme.