Listeners were presented with a sequence of sinusoidal tones, each tone 250 msec in duration and with no gap between adjacent tones. All tones were either 400 or 800 Hz, and these frequencies were presented in strict alternation. This sequence of alternating tones presented at equal amplitude to both ears simultaneously for 20 sec. However, when one ear received 800 Hz, the other received 400 Hz and vice versa. Under these conditions 48% of 42 right-handed listeners perceived a single tone oscillating from ear to ear whose pitch also oscillated from one octave to the other in synchrony with the localization shift and with the higher pitch localized in the right ear. When the identical sequence was again presented but with earphones reversed, these listeners reported the identical percept with the higher pitch still localized in the right ear. Two listeners with absolute pitch identified the alternating pitches as G4 (392 Hz) and G5 (784 Hz). Another 14% of the listeners obtained the same illusion but with the high pitch consistently localized in the left ear. The remaining 38% reported a variety of percepts, but no listener perceived the stimulus correctly. A similar illusion also occurs with two frequencies arbitrarily chosen from within this octave range.