Abstract: The object of the invention is to provide a method and a device for operating a premix burner which improve the supply of fuel under certain types of operation.According to the invention, this is achieved by the fact that the liquid fuel (2) and the water (27) are conveyed separately to the liquid-fuel nozzle (17), and only there a liquid-fuel/water mixture (28) is produced, which is then injected into the inner chamber (9) of the premix burner (4) in a plain jet (29) with an injection angle a of less than 10.degree.. To this end and, the liquid-fuel nozzle (17), which opens out centrally into the inner chamber (9), is designed with a simple injection opening (19). A mixing zone (22), into which a liquid-fuel line (20) and a water feed line (21) open out, is arranged upstream of the injection opening (19).