A rear steer portable wheelchair having; (a) a pair of side frame assemblies (2, 3) each having an upper tube member and a lower tube member and forward and aft sections (6, 7); and (b) a scissor hinge assembly mounted on the side frame assemblies (2, 3), which scissor hinge assembly extends at a central position between the side frame assemblies (2, 3), which hinge assembly is foldable from between an in-use position to a collapsed position, wherein the scissor hinge assembly includes a pair of geared hinge linkages (24, 25), which are adapted to produce a locked hinge arrangement (c) a pair of front wheels with each front wheel being attached to the forward section of the side frame assemblies (2, 3), (d) a pair of rear steer wheels adapted for steering with each rear steer wheel being attached to the aft section of the side frame assemblies (2, 3), (e) a pair of collapsible pushing arms that are attached to the side frame assemblies (2, 3), wherein the pushing arms each include a locking pin which is adapted to produce a locked pushing arm arrangement, (f) a pair of arm rests that are attached to the side frame assemblies (2, 3), (g) a back support means, which is attached to the aft section of at least one of the side frame assemblies (2, 3); and (h) a seat support that extends above the scissor hinge assembly and between the side frame assemblies (2, 3); wherein in use the wheelchair is deployed by (i) spreading the side frame assemblies (2, 3) apart to pull the scissor hinge assembly into a locked position and (ii) putting the pair of foldable pushing arms into a locked in-use position and further wherein in use the wheelchair is collapsed by (i) pulling a handle proximate the central position of the scissor hinge assembly to release the locked position of the scissor hinge assembly to pull the side frames assemblies (2, 3) together, and (ii) collapsing the collapsible arms from their in-use locked position to a folded out of use position into a compact, readily lifted and transportable configuration. (a) a pair of side frame assemblies (2, 3) each having an upper tube member and a lower tube member and forward and aft sections (6, 7); and (b) a scissor hinge assembly mounted on the side frame assemblies (2, 3), which scissor hinge assembly extends at a central position between the side frame assemblies (2, 3), which hinge assembly is foldable from between an in-use position to a collapsed position, wherein the scissor hinge assembly includes a pair of geared hinge linkages (24, 25), which are adapted to produce a locked hinge arrangement (c) a pair of front wheels with each front wheel being attached to the forward section of the side frame assemblies (2, 3), (d) a pair of rear steer wheels adapted for steering with each rear steer wheel being attached to the aft section of the side frame assemblies (2, 3), (e) a pair of collapsible pushing arms that are attached to the side frame assemblies (2, 3), wherein the pushing arms each include a locking pin which is adapted to produce a locked pushing arm arrangement, (f) a pair of arm rests that are attached to the side frame assemblies (2, 3), (g) a back support means, which is attached to the aft section of at least one of the side frame assemblies (2, 3); and (h) a seat support that extends above the scissor hinge assembly and between the side frame assemblies (2, 3);