A computer housing, which comprises a hollow frame structure having two opposite rails at the top and a base board at the bottom, two side panels having each a plurality of T-shaped hooks projecting from its bottom edge respectively fastened in corresponding T-shaped holes on the base board and an U-shaped portion on its top edge, an upper cover mounted on the two rails of the frame structure with its two opposite channel edges respectively engaged with the U-shaped portions of the two side panels, and a front panel fixedly secured to the front surface of the frame structure by means of screws permitting the bevel front edge of the upper cover to be retained in an upper channel which is made on its top edge.