We have recently shown that collagen activates platelets through a pathway dependent on the Fc receptor γ-chain and the tyrosine kinase Syk. We report here that the Fc receptor γ-chain and the candidate collagen receptor glycoprotein VI (GPVI) co-associate. Furthermore, cross-linking GPVI stimulates a similar pattern of tyrosine phosphorylation to that stimulated by collagen, including tyrosine phosphorylation of Fc receptor γ-chain. These results support a model where GPVI couples collagen-stimulation of platelets to phosphorylation of the Fc receptor γ-chain leading to activation of Syk and phospholipase Cγ2.