The Derjaguin-Landue-Vervey-Overbeek (DLVO) theory predicts that an isolated pair of charged colloidal spheres experience purely repulsive screened Coulomb interaction at large interparticle separations. Many evidences, which suggest the existence of long-range attractive component in the interparticle interaction, have emerged contradicting the prediction. These evidences include gas-liquid, gas-solid transitions, existence of stable voids, metastable colloidal crystallites and reentrant transitions in dilute suspensions. Some of these observations have triggered several experimental and theoretical investigations to probe the pair-potentialU(r)between like-charged in very dilute suspensions. Existence of long-range attraction inU(r)has been observed only when like-charged glass walls confine like-charged particles. Though some theoretical models predicted the existence of long-range attraction in the effective pair-potential, a clear and consensus picture is still awaited. This paper briefly reviews the experiments and theoretical results that have dealt with long-range attraction in colloidal systems. The paper presents in detail the recent studies of structural ordering in a novel two dimensional (2D) system of like-charged large metal balls. Interestingly, these studies reveal the existence of long-range attraction in the pair-interaction of like-charged metal balls spread on a dielectric surface, and the occurrence of gas-liquid transition upon variation of the area fraction of the charged metal balls. ©2000 American Institute of Physics.