In this study, poly(DMAEMA-AMPS-HEMA) terpolymer/montmorillonite nanocomposite hydrogels were prepared by in situ polymerization technique using 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA), 2-acrylamido-2-methlypropane sulfonic acid (AMPS), 2-hydroxyethyl methacrylate (HEMA) monomers in clay suspension media. N,N-methylenebisacrylamide (NMBA) was used as crosslinker and potassium persulfate/potassium bisulfide were used as initiator and accelerator pair. The water absorption capacities and acidic dye (indigo carmine) adsorption properties of the nanocomposite hydrogels were investigated. Adsorption properties of the hydrogels were investigated at different conditions such as different initial dye concentration and contact time. The concentrations of the dyes were determined using UV/Vis Spectrophotometer at wavelength 610 nm. Langmuir and Freundlich isotherm models were used to describe adsorption data and the results clarified that these models were the best-fit for the adsorption of indigo carmine.