The 1∕f noise in carbon nanotube random network films has been experimentally and theoretically investigated. The authors have established that the percolation process is the primary physical mechanism influencing the noise level in such films. Using percolation theory, the authors give an expression for the 1∕f noise scaling that describes how noise is affected by design variables of nanotube macrostructures. As expected for percolation networks, the noise amplitude strongly depends on the film homogeneity. This shows that noise analysis could be used as a tool to evaluate the quality of films.