PURPOSE: We investigated the effects of the anti-epilepsy drug valproic acid (VPA) alone and in combination in treating cervical cancer. METHODS: VPA was investigated for its effects on cervical cancer Hela cell proliferation and tumor growth via in vitro and in vivo assays. RESULTS: VPA induce cell growth suppression and cell cycle arrest, with an increase of Notch1 that acts as a tumor suppressor and the change of other tumor-associated genes such as p21, p63 and PCNA. VPA was also found to induce cell morphological change, with an increase of certain cell transformation markers such as snail1, snail2 and N-cadherin. Moreover, VPA could significantly up-regulate somatostatin receptor type II (SSTR2). Our in vivo study further demonstrated that VPA via inducing SSTR2 up-regulation extremely enhanced the anti-tumor ability of the SSTR2-preferential cytotoxic COL-SST conjugate in xenografts. CONCLUSIONS: VPA could not only suppress tumor progression but also provide a novel promising therapeutic choice in combination with a receptor-targeted cytotoxic conjugate via activating the specific receptor.