A simulation technique is presented for imaging multiple objects in microwave region. The proposed technique is based on the time-reversed finite-difference time-domain method (FDTD-TR) in three dimensions. Using this technique, not only the locations of objects but also their detailed images can be obtained. The method is capable of imaging hidden objects with transmission as well as reflection imaging modalities in the nearfield and far-field. The proposed technique is computationally efficient due to using a much smaller data set compared to conventional FDTD-TR imaging techniques where the entire time span of the captured data is reversed. The method was validated using experimental results as well as simulations.