In this paper, we will apply the regularized channel inversion (RCI) combined with one of the 5G waveform candidates, namely generalized frequency division multiplexing (GFDM), in multiuser MIMO downlink systems. RCI, known as the simplest linear precoding based on MMSE criterion, performs well on previous multiuser MIMO systems using orthogonal frequency division multiplexing (OFDM) in order to reduce the effect of inter user interference (IUI). This paper will present how the RCI in the multiuser MIMO-GFDM systems performs such good results as the RCI implemented in the multiuser MIMO-OFDM systems based on bit error rate (BER) parameter without causing significant increase in system complexity. Moreover, the proposed system using GFDM shows good result in terms peak-to-average power ratio (PAPR) value. On systems using GFDM, we develop two systems employing 16-QAM and 16-OQAM, respectively, to show the difference of both systems. In addition to provide the performance of RCI in the multiuser MIMO-GFDM system, this paper also presents the performance of RCI in the multiuser MIMO-GFDM system with different number of users.