The just‐noticeable difference (jnd) in interaural time delay for a narrow‐band noise signal has been measured for ten interaural conditions of wide‐band masking noise. The narrow‐band signal is a one third‐octave noise band at 500 Hz. The masking noise covers 250–1500 Hz. Both signal and masker have an overall level of 56 dB SPL. The masked jnds for narrow‐band noise are consistent with those for tones [M. F. Cohen, J. Acoust. Soc. Am.64, S35(A) (1978)] in that the progression of increasing difficulty (increasing jnds) is interaurally identical musket (NO), uncorrelated masker (NU), and antiphasic masker (Nπ). Note that this progression is exactly opposite to that expected from detectability results. Other interaural conditions of the masker include an interaural delay of τ = 100 μs (Nτ), an interaural attenuation of α dB (Nα), or both (Nτ,α), where α is realized by attenuating one ear and is chosen for each subject to center the masker when both τ and α are present. The jnds with these maskers show that theNτ,α case is more difficult thanNτ orNα. [Work supported by NIH.]