A drive for adjusting parts of seating and reclining furniture is provided, which includes: an electric motor, disposed within a motor cover of a cabinet and engaged with a gear connected to a lead screw via one end of a drive shaft of the electric motor, and a slider, for moving rectilinearly back and forth in cooperation with the lead screw. The slider is provided with a drive nut therein, which is screwed onto the lead screw to enable the slider to move rectilinearly. One or more positioning grooves are disposed on the slider in parallel with the nut. Guide rails are correspondingly disposed in the positioning grooves. One end of each guide rail is fixed to the cabinet and the other end of each guide rail is fixed to a top stopper. Therefore, a better adjustability is achieved within a limited inner space of the furniture. Moreover, the drive does not need to move, and the stroke length of the drive is independent from the cabinet size thereof, so that the drive has a low manufacturing cost and is easily assembled.