A valve insert (8a, 8b) for a valve, in particular for a control valve (2) for controlling pressure-medium streams of a camshaft adjuster, includes an insert housing (10), in which a filter (12) and a non-return valve (14) with a closing element (24) and a seat element (20) are integrated. A configuration of the valve insert which is easy to install is ensured by at least the insert housing (10), the filter (12) and the seat element (20) being connected non-detachably to one another and forming one preassembled structural unit (40).