The invention relates to a method for checking the regulation state of a frequency-stabilised laser system comprising a laser (2). At least one first sidebrand frequency VHF is modulated to the laser beam (1) of said laser, the laser beam being guided through an absorption material (13) comprising a plurality of absorption lines in a detuning region of the laser (2), said absorption lines being arranged at different distances from each other. The laser frequency V.sub.L is detuned and, as a regulation signal for the laser frequency V.sub.L, it is determined whether there has been an absorption in the absorption material. The inventive method is characterised in that a second sidebrand frequency V.sub.FG is modulated to the laser beam (1), said frequency being at a known distance defined by a frequency generator (29) in relation to the laser frequency V.sub.O; in that the absorption of the second sidebrand frequency V.sub.O+V.sub.FG in the absorption material is checked at least from time to time; and in that when no absorption is observed for the second sidebrand frequency, the laser frequency V.sub.L is detuned until an absorption of both the laser frequency VO and the second sidebrand frequency V.sub.O+V.sub.FG is observed.