Abstract: A chair comprising a seat (12,19) having an upstanding backrest (11,20) and a depending leg structure (13,14), with the leg structure terminating in front and rear friction-producing formations (17,18) normally engaged with the ground in a stable disposition for the chair, and the chair additionally having a roller assembly (22,23) in a configuration which extends rearwardly of and across the chair, and which is elevated from the ground with a front-to-rear upward inclination in the normal disposition, whereby the chair can adopt a stable mobile disposition by rearward tilting to engage the roller elements with the ground.