Music cognition research has provided evidence for the benefit of temporally regular structures guiding attention over time. The present study investigated whether maintenance in working memory can benefit from an isochronous rhythm. Participants were asked to remember series of 6 letters for serial recall. In the rhythm condition of Experiment 1A, a wood block sound was presented 6 times with a regular stimulus-onset-asynchrony during the delay between encoding and recall. In the silent condition, no sound was presented. The presence of the regular rhythm resulted in improved memory performance (Experiment 1A.), an effect also observed under articulatory suppression (Experiment 2), suggesting that temporal regularities can enhance maintenance in working memory including attentional refreshing. Experiment 1B confirmed this interpretation by showing that the presentation of a nonisochronous rhythm did not result in improved memory performance in comparison to a silent condition. The findings are discussed in relation to current working memory models and the theoretical framework of dynamic attending.