Recently, some groups including ours found that some ganglioside species could specifically modulate the certain protein kinase activities on the cell surface membrane. We show here two representative cases. One is the ganglioside-dependent modulation of autophosphorylation of EGF or PDGF receptors, by which altered the cell growth. Another is the ganglioside dependent ecto-type protein kinase activities on the cell surface of a human neuroblastoma cell line, GOTO. The latter activities may be closely correlated with the ganglioside GQ1b dependent neuritogenesis.