This paper deals with the hearing of complex low frequency tones. Hearing thresholds of low frequency pure tone and complex tones were measured. The measurement frequencies are from 5Hz to 50 Hz. In the results, the hearing thresholds of complex tones are found to be lower than those of pure tones, whose frequencies are the same as the fundamentals. Hearing thresholds of complex tones are affected by the phase difference between fundamental and harmonic. This means that the hearing of a complex tone is influenced by a higher harmonic component though the component is not audible. The results are not in agreement with the audibility of complex tones in the middle frequency area. The complex low frequency tone is not heard separately as each component but is heard as one complex wave.