Systematic effects on intensity discrimination occur in listeners who have experienced long‐term unilateral amplification [Robinson and Gatehouse, J. Acoust. Soc. Am.97, 1183–1190 (1995)]. For a bandlimited tone complex centered at 3 kHz, the normally aided ear showed better discrimination performance than the unaided ear at sound‐pressure levels greater than 85 dB, yet was worse than the unaided ear at lower levels. No effects were found at 0.25 kHz. In the present study, intensity discrimination was investigated prospectively for five listeners with bilateral, sensorineural, hearing impairment following provision of unilateral amplification. The stimuli were the same as those used previously. Weber functions for both ears were similar at both frequencies prior to fitting the aid, and 4 to 12 weeks postfitting. From 15 weeks, the normally aided ear showed better discrimination performance than the unaided ear at 3 kHz for a sound‐pressure level of 95 dB. No effects were observed at 0.25 kHz, or for the unaided ear. Hence, changes in intensity discrimination occur in the normally aided ear following long‐term exposure to the frequency‐gain characteristics of unilateral amplification. Further research should examine the generality of these results to other listeners, and show whether it extends beyond intensity discrimination to other psychoacoustic capabilities.