Remodelling of nucleosomes on DNA controls access of regulatory proteins to their target sequences. In this way, it endows chromatin with the plasticity required for regulation of transcription, DNA replication, recombination and repair. A variety of large, ATP-dependent multiprotein complexes carry out such remodelling, and these have been identified in yeast, flies and mammals. In Cell Science at a Glance, Anton Eberharter and Peter Becker survey the known remodelling machines, as well as the different `nucleosomoid' structures that they generate (see p. 3707 + poster).