A method for operating a two-roll casting machine for casting molten metal into cast strip, which machine has two casting rolls which are each rotatively driven in opposite directions about an axis of rotation and between them delimit a casting gap on its longitudinal sides, with side plates that can be placed on the casting rolls, which side plates seal the casting gap on its narrow sides in the casting operation, bridging the casting gap with a refractory material, wherein the side plates are moved during the casting operation in a direction which is aligned parallel to the direction of conveying in which the cast strip leaves the casting gap. With such a method the formation of grooves distorting the casting result and the casting operation can be suppressed with increased certainty and the service life of the side plates can be increased, compared to the prior art.