Thresholds for 2‐kHz sinusoidal signals were determined in the presence of a notched‐noise masker, for six normal‐hearing listeners and 12 listeners with cochlear hearing losses. Following Patterson and Nimmo Smith [J. Acoust. Soc. Am.67, 229–245 (1980)], conditions were used where the notch was placed both symmetrically and asymmetrically about the signal frequency. The auditory filter shape for both the low‐ and high‐frequency side of the filter was calculated using the rounded‐exponential form of the filter. In six hearing‐impaired listeners, the auditory filter shape showed a shallow low‐frequency skirt indicating pronounced susceptibility to the upward spread of masking. In two hearing‐impaired listeners, the filter shape showed a shallow high‐frequency skirt, indicating pronounced susceptibility to the downward spread of masking. Two other listeners with mild threshold losses had steeper and more symmetric filters than normal, suggesting either a small conductive loss or an attenuation factor of sensorineural origin not associated with a degradation of frequency resolution. In the remaining two listeners, the auditory filter had too little selectivity for its shape to be reliably determined.