Binding of native connectin (2, 100 kDa fragment of α-connectin) to myosin filaments was investigated using a sedimentation technique and densitometric estimations of the separated proteins. In the presence of 60 mM KCl and 5 mM phosphate buffer, pH 7.0, as much as 1.5 mol of connectin was bound to 1 mol of myosin, suggesting that some 150 connectin filaments bound to a single myosin filament of approximately 0.5 μm in length. This value was much more than the ratio found in muscle (12:1). It appeared that C protein did not affect the binding of connectin to myosin filaments.