A back light assembly is provided to reduce the mold cost for manufacturing a bottom chassis and to separate a bottom chassis into a bottom member and a side member, thereby reducing the entire manufacturing cost. Plural lamps(200) are arrayed in parallel with each other. A bottom chassis(300) covers sides of the lamps. A side chassis(400) is combined with an edge of the bottom chassis and receives the lamps together with the bottom chassis. The side chassis includes a combining member combined with the bottom chassis. The first side is extended from the combining member and covers the lamps. The second side is extended from the first side to the outside of the bottom chassis. The third side is extended from the second side toward the first side. The first burring is formed at the edge of the bottom chassis. The first screw hole is formed at the combining member and combined with the first burring by screws.
