Variance fluctuations in band‐limited vacuum‐tube flicker noise, current noise in a germanium p‐n junction, and current noise in a carbon resistor are measured by determining probability amplitude distributions of the noise signals with a multichannel pulse‐height analyzer. The variances of 30 noise specimens, each 100 sec in duration, for the three noise sources are obtained from the width of the probability amplitude distributions, all of which obey a normal‐distribution law. Fluctuations in variance are largest in the case of resistor current noise and least for current noise in a p‐n junction. Even in the latter case, however, the variations are well in excess of artifacts resulting from sampling errors, as demonstrated by examining Nyquist noise signals. It is concluded that all three 1/fnoise sources exhibit variance fluctuations to varying degrees.