A multiplexed input/output (I/O) system detects leakage currents on a selected input channel. The system includes a leakage detection multiplexer connected to provide an output selected from one of a plurality of input channels. In addition, the leakage detection multiplexer provides as part of the output measured leakage currents associated with the selected input channel. Based on the detected leakage currents, a determination can made regarding whether the detected leakage currents have compromised the integrity of the multiplexer output. In addition, the detected leakage current can be used to compensate the output provided by the multiplexer to account for the presence of leakage currents on the selected channel.