In the monomode optical fiber transmission system, the effective cutoff wavelength of the first higher order mode is one of the most important design parameters. In general, the effective cutoff wavelength is somewhat shorter than the theoretical cutoff wavelength, resulting in a more robust design that allows the system to operate at a higherVvalue and thereby reducing the loss of the fundamental mode in the core. In this work, the bending method and power step method are used to measure the effective cutoff wavelengths for matched‐cladding and depressed‐cladding fibers, and the results are compared for these two types of fibers.