Abstract: A column system for chromatography is provided which comprises (1) a supporting structure for column units having a pair of upright end frames interconnected by pairs of horizontal slide rails at different levels, each pair of slide rails at an individual level being adapted slidably to carry a platform movable along said slide rails, said slide rails being disposed inboard of the uprights of the end frames so that a platform may be slid into and out of engagement with the slide rails by passing through at least one of the end frames, and stop means for preventing unintentional movement of a platform off its associated slide rails; and (2) a plurality of platforms each carrying an individual column unit, each platform including clamping means for securing the platform in a desired position along the slide rail pair on which it rests, said clamping means being integrated with said stop means.