In pending application Ser. No. 155,292, now U.S. Pat. No. 4,384,713, filed June 2, 1980, there is shown and described a walker comprising side frames provided with handrails at the top which may be grasped to support the user and wheels at the bottom to enable rolling the walker. There is lever controlled means mounted to each side frame for braking and releasing the wheels and a transmission member extending from one side to the other which enables braking and releasing the wheels from either or both sides. In the aforesaid application, the side frames are not foldable. The purpose of this invention is to provide a foldable walker which can be folded and unfolded without having to dismantle or disconnect any of the structural and/or operative parts thereof, an undertaking which is generally not within the capacity or skill of the average patient.