MicroRNAs can coordinately repress multiple target genes and interfere with the biological functions of the cell, such as proliferation and apoptosis. In the present study, we report that miR-200b was downregulated in malignant glioma cell lines and specimens. Overexpression of miR-200b suppressed the proliferation and colony formation of glioma cells. An oncogene encoding cAMP responsive element-binding protein 1 (CREB1), which has been shown to be an important transcription factor involved in the proliferation, survival, and metastasis of tumor cells, was here confirmed as a direct target gene of miR-200b. CREB1 was also found to be present at a high level in human glioma tissues. This was inversely correlated with miR-200b expression. Ectopic expression of CREB1 attenuated the growth suppressive phenotypes of glioma cells caused by miR-200b. These results indicate that miR-200b targets the CREB1 gene and suppresses glioma cell growth, suggesting that miR-200b shows tumor-suppressive activity in human malignant glioma.