In Saccharomyces cerevisiae, known histone acetylation sites regulating gene activity are located in the N-terminal tails protruding from the nucleosome core. We report lysine 56 in histone H3 as a novel acetylation site that is located in the globular domain, where it extends toward the DNA major groove at the entry-exit points of the DNA superhelix as it wraps around the nucleosome. We show that K56 acetylation is enriched preferentially at certain active genes, such as those coding for histones. SPT10, a putative acetyltransferase, is required for cell cycle-specific K56 acetylation at histone genes. This allows recruitment of the nucleosome remodeling factor Snf5 and subsequent transcription. These findings indicate that histone H3 K56 acetylation at the entry-exit gate enables recruitment of the SWI/SNF nucleosome remodeling complex and so regulates gene activity.