This study evaluates the applicability of using microwaves for the inspection of pipe wall thinning by using numerical simulations and experiments. The configuration considered in this study is an axisymmetric one consisting of a straight brass tube and coaxial cables. After the agreement between three-dimensional numerical simulations and experimental result is confirmed, experiments to locate wall thinning are carried out. Clear signals due to the wall thinning are obtained. The time of flight of microwaves agrees with the theoretical prediction, which demonstrates the possibility of locating wall thinning from microwave signals.