Curcumin (CUR) is a natural agent that has been demonstrated to effectively inhibit prostate cancer growth. However, natural CUR is relatively unstable and can be easily degraded in vivo. Therefore, it is essential to develop other stable curcuminoids. Demethoxycurcumin (DMC) is a candidate that has been verified in several tumor types and has potential for the treatment of prostate cancer. In the present study, we investigated the effects of DMC on proliferation, apoptosis and migration of PC-3 cells. MTT assay results indicated that DMC inhibited PC-3 cell viability in a dose- and time-dependent manner, and DMC induced G2/M phase arrest. Furthermore, PC-3 cells in DMC-treated groups had a higher apoptotic rate compared with DMSO-treated control. This effect may be due to the activation of the caspase-3 pathway. In DMC-treated groups, migrating and invasive cells were dramatically reduced (P<0.05). The activity of MMP-2, which is correlated with migration and invasion was also suppressed by DMC. These results indicated that DMC may inhibit PC-3 cell migration and invasion partially by affecting MMP-2 activity. In conclusion, DMC significantly inhibits proliferation, migration and invasion of cultured PC-3 cells, and this study may provide evidence for future in vivo studies and clinical use.