A seat slide structure (10) includes upper (12) and lower (14) track members having U-shaped leg portions (18, 28) which interfit with each other. The track members (12, 14) are spaced apart and laterally located by plastic slides (36) which fit between the base (16) of the upper track member (12) and bight portions (34) of the legs (28) of the lower track member (14). A locking plate (50) is vertically movable within the upper track member (12) and includes spaced pairs of locking portions (52) engageable with spaced pairs of locking notches (62) in the bight portions (34) of the legs (28) of the lower track member (14) to provide a dual latch locking the upper track member (12) in a horizontal position relative to the lower track member (14). The locking plate (50) is releasably biased to a locked position and is released by a release lever (64) engageable therewith upon pivoting movement of the lever (64) relative to the upper track member (12).