This paper gives the results of analytical and experimental data on localization of structural damage, obtained through comparison of vibration modes for intact and damaged structure. The paper studies a standard dog-bone sample used for highcycle fatigue tests, the analysis being performed for its finite-element model. Necking damage of the sample was simulated by step-by-step elimination of elements from the model. Physical tests were performed as per the same approach. This paper studies the following damage localization methods: direct method of shape variation; shape curvature method and damage index method. The analysis of vibration shapes performed as per various approaches yielded damage locations and made it possible to identify the most accurate of above-mentioned methods.