The present invention relates to a scroll pump (10) comprising a pump housing (12), a drive shaft having a concentric shaft portion (14) and an eccentric shaft portion (16) connected to an orbiting scroll. The shaft is arranged to be driven by a motor (18) so that during use rotation of the shaft imparts an orbiting motion to the orbiting scroll relative to a fixed scroll (22) for pumping fluid between a pump inlet (24) and pump outlet (26) of the compressor. The fixed scroll has an opening through which the shaft extends and is connected to the orbiting scroll on an opposing side of the fixed scroll to the motor. A high vacuum region is located on an orbiting scroll side of the scroll arrangement and a low vacuum region is located generally on a fixed scroll side of the scroll arrangement. A lubricant free anti-rotation device (52) is located in the high vacuum region for resisting rotation of the orbiting scroll and allowing said orbiting motion, and a bearing arrangement (34, 36) for supporting rotation of the concentric shaft portion and eccentric shaft portion is located in the low vacuum region.