Myoelectric signal (MES) data were obtained from remnant muscles in residual upper limbs and analogous intact muscles of thirty-two upper-limb deficient subjects. Spectral parameters (mean frequency, median frequency, and equivalent statistical bandwidth) of the MES were calculated and examined for significant differences between the remnant muscle data and intact muscle data. Other factors were examined for possible significant effect on the spectral content of the MES. Although no pattern of spectral difference between the MES of residual versus intact limb muscles was found, spectral differences were apparent by visual inspection in most cases. Level of amputation (above elbow or below elbow) was the sole factor found to have a significant effect on the MES spectral content. Data were separated based on level of amputation; no statistically significant difference between the spectral parameters of residual versus intact muscle MES was found. However, greater variation in the spectral parameters of the remnant muscle data was observed. The results of this study add to one's knowledge of the MES characteristics of remnant muscles, with implications for the design of myoelectric controllers.< >