Moore [J. Acoust. Soc. Am.54, 610–619 (1973)] has suggested that under the assumptions of a place or excitation‐pattern theory of frequency discrimination, frequency DLs should be dependent on auditory excitation‐pattern slopes only for long‐duration tones with spectral slopes that are steeper than those of the excitation pattern. Otherwise, according to this theory, it is the slopes of the stimulus spectrum that limit the frequency DL. In this paper, we extend these ideas to evaluate the prediction that for very short, spectrally broad tones, frequency DLs obtained from hearing‐impaired subjects should not differ systematically from those obtained from normal‐hearing listeners. Frequency DLs were obtained as a function of intensity at 500, 1000, and 2000 Hz for 5‐ and 300‐ms pure tones in normal‐hearing and moderately hearing‐impaired subjects. The DLs obtained from hearing‐impaired subjects were larger than normal for long‐duration but not short‐duration pure tones; these results are consistent with the predictions of the excitation‐pattern theory. However, an unexpected but consistent finding of nonmonotonic frequency DL‐intensity functions in the 5‐ms condition in normal‐hearing subjects complicates interpretations of the results.