We examined effects of auditory streaming on synchrony-asynchrony discrimination of audio-visual and audio-audio stimuli. Tone sequences were four repetitions of a triplet pattern comprising a low-frequency tone (L) and a high-frequency tone (H). The frequency difference (DF) between L and H was either approximately 0, 1/12, 1/6, 1/3, 1/2, or 1 octave, centered at 1 kHz. Each tone was 33.2 ms. The stimulus onset asynchrony of adjacent tones was randomized. The cross-modal stimulus was a luminance-modulated Gaussian blob. The intra-modal stimulus was white noise. Both stimuli were 8.3 ms. Experiment 1 measured synchrony-asynchrony discrimination limens of blob-tone stimulus onsets using the 2IFC paradigm with a 2-up 1-down method under six DF conditions. Results demonstrated that discrimination improved for flash-tone pulse trains at DF between L and H greater than 1/6 octave. Experiment 2 measured synchrony-asynchrony discrimination limens of noise-tone stimulus onsets using the method described for Experiment 1. Results showed that discrimination declined for noise-tone pulse trains at DF between L and H greater than 1/6 octave. Although the directions of the effects of streaming differed between cross-modal and intra-modal perception, these results suggest that the same system of auditory streaming influences synchrony perception within and across modalities.