Method and device to control the axial position of slabs emerging from continuous casting applied in rolling plants comprising at least a casting machine (11), an extraction and straightening assembly (12) with pairs of rolls (25), a heating and/or temperature maintenance furnace (15) and a roughing and pre-finishing (16) or finishing train (19), said device comprising means (26, 31a, 31b) to detect the axial position of the slab (24) arranged in at least a position upstream of or inside said furnace (15) and a processing unit (30) able to receive from said means (26, 31a, 31b) the signal relating to the axial position of the slab (24) and to condition the activation of at least one of said pairs of rolls (25) of the extraction and straightening assembly (12) to obtain a differentiated pressing of the slab (24) in the direction of the width in order to at least partly eliminate a possible discrepancy (Δ) of the axis (28) of the slab (24) with respect to the rolling axis (27).