A device for determining the frequency of a dominant tone of a tinnitus perceived by a patient. A tone generator plays tones, an input unit receives patient evaluations, and a controller carries out a similarity measurement and a comparison of pairs of tones. The controller controls the tone generator for the similarity measurement to generate successive tones, and, after playing a respective tone, receive patient's evaluation regarding the similarity of the tone to the dominant tone of the tinnitus. The controller also controls the tone generator for the comparison of pairs of tones to play successive pairs of tones, and, after playing a respective pair, receives the patient's evaluation as to which tone of the pair is more similar to the at least one dominant tone of the tinnitus. Using the results, the frequency most similar to the frequency of the dominant tone of the tinnitus can be determined.