Previous studies have suggested that elimination of auditory feedback has no significant effect on the accuracy of keyboard performance. In the present study, this issue was investigated further by focusing specifically on parameters of expression in piano performance: horizontal and vertical timing, horizontal and vertical dynamics, and pedaling. Six pianists performed a short musical excerpt (bars 1-5 of Chopin's Etude in E Major, op. 10, no. 3) 10 times on a digital piano in each of four conditions: expressive with and without feedback, and metronomic with and without feedback. The data analyses revealed significant effects of feedback deprivation on all expressive parameters in both expressive and metronomic performance. However, these effects were very small, except for some substantial changes in pedaling by some pianists. To determine the perceptual and aesthetic significance of these effects, a group of pianist listeners was presented with a forced- choice test in which expressive performances produced with and without feedback were paired with each other. The listeners correctly identified the performance played without feedback on only 63.5% of the trials, which confirms the relative subtlety of the effects of feedback deprivation. Although expression seems to be controlled primarily by an internal representation of the music, auditory feedback may be important in fine-tuning a performance and in the control of pedaling. However, it is also possible that the effects of auditory feedback deprivation merely reflect a lack of motivation to play expressively in the absence of sound.