In this study, the effects of nonionizing electromagnetic fields (EMF; 925 MHz) on the OmpF porin channel have been characterized at the single-channel level. Channel activity was recorded in real time by the voltage clamp method. Our results showed an increase in the frequency of channel gating and voltage sensitivity. The effects of EMF lasted for several milliseconds after the field source was terminated. However, the conductance levels of channels did not change significantly. Thermal effects of EMF on single-channel properties are a possible cause, based on theoretical evaluation of results that were comparable to those seen in conventional experiments at different temperatures. We conclude that EMF affects both the dynamics and conformation of the channel, either directly by affecting critical amino acid side-chain arrangement, or indirectly, via the electrolyte or the lipid membrane.