When dealing with water soluble dyes conventional treatments, such as biological processes and coagulation/flocculation processes, are often unable to provide satisfactory colour removal. This leads to the use of adsorption as one of the most effective methods. Traditionally, activated carbon has proven to be effective in adsorbing various water soluble dyes, however high activation and regeneration costs are disincentives for its use. Hence, some cheap materials derived from industrial and agricultural waste as well as mineral and coal processing have been investigated as alternatives to activated carbon. Brown coal has some similarities to activated carbons, particularly its high porosity and high adsorption capacity in some cases. In this study, both raw and treated brown coal were evaluated as adsorbents for both anionic and cationic model dye solutions and the performance of these materials were compared against coal-based activated carbon. From the kinetic and equilibrium data, a mechanism that describes interaction between brown coal and cationic or anionic dyes is proposed. Coal based activated carbon showed good performance for both cationic and anionic dyes, as indicated by high adsorption capacities (qe). In contrast, brown coal exhibited good adsorption for only the cationic dye. The qe value for the anionic dye was only 15% of that for the cationic dye. It is suggested that the hydroxyl and carboxyl groups in the brown coals play an important role in interacting with the positively charged dye molecules and that chemisorption is one of the mechanisms involved.