A method for limit level monitoring with a radiometric limit switch. A detector measures discrete radiation intensities. Statistical distributions of radiation intensities in a state, free of medium, and in a state, covered by medium, are given by two Poisson distributions. In an interval successive radiation intensities are measured, a distribution of the radiation intensities, two separated Poisson distributions are identified within the distribution, based on the positions of the Poisson distributions identified within the distribution, an upper threshold value is determined for the radiation intensity, the exceeding of which upper threshold value by a radiation intensity measured following the interval means a state change into the state, free of medium, has been detected, and/or a lower threshold value is determined for the radiation intensity, the subceeding of which lower threshold value by a radiation intensity measured following the interval means a state change into the state, covered by medium, has been detected.