The 3’ untranslated region (3’ UTR) of eukaryotic mRNA is an important regulation element that affects not only mRNA translation, but also cell growth. We had found that the 3’ UTR of CCAAT-enhancerbinding protein 13 (C/EBPβ) mRNA had tumor suppression activity. Herein, we reported that deletion of two short sequences at both termini of the C/EBPβ 3’UTR reduced the tumor suppression activity of this 3’ UTR, as demonstrated by reduced cell growth, colony formation ability, and tumorigenicity in nude mice. It is noteworthy that the only deletion of a single such sequence was enough for the reduction of tumor suppression effect, and the reducing effect of deletion of the sequence near 3’ terminus was stronger. Therefore,specific short sequences in the C/EBPβ 3’ UTR are crucial for the tumor suppression activity of C/EBPβ.