Batch studies were conducted to investigate the potential of untreated teak leaf powder (TLP) to remove color from synthetic and industrial effluents. Langmuir and Freundlich isotherms were used to analyze the equilibrium data. Langmuir isotherm was found to be the best-fitting isotherm. The monolayer adsorption capacity was found to be 99.1, 145.2, 188.7 and 207.9 mg methylene blue/g TLP at 293,303,313 and 323 K, respectively. It was also found from the thermodynamic analysis that the adsorption of methylene blue onto TLP was spontaneous, chemisorption and exothermic in nature. The color of the effluent was quantified in terms of the area under absorbance spectrum. Percentage color, COD and total dissolved solids (TDS) removed from a diluted effluent (10% effluent by vol.) were found to be 57.41, 45.95 and 49.46, respectively. The monolayer capacity was calculated in terms of TDS and was found to be 219 mg/g. (C) 2009 Elsevier B.V. All rights reserved.