p16 ( INK4α ), an inhibitor of cyclin-dependent kinase 4 and 6, has been proposed to play an important role in cellular aging and in premature senescence. The expression of the p16 ( INK4α ) is primarily under transcriptional control. Our previous data showed that a negative regulation element lies in its promoter. In that element, a MYB-binding site (MBS) was uncovered by transcription analysis. Here, we report that MBS is a negative regulation element and B-MYB binds to this site in vivo. In human embryonic lung fibroblast cells, B-MYB downregulated p16 ( INK4α ) expression, whereas knocking down of B-MYB upregulated it. Evidence also showed that overexpression of B-MYB in cells could increase the number of utmost passage and decrease G1 block, whereas knocking down of B-MYB could impair their replicative ability. This study provides evidence of the capacity of B-MYB not only to regulate p16 ( INK4α ) expression but also the phenotypic consequence on cellular senescence.