In the present study cellulose extracted from the pine needles of P. wallichiana was crosslinked with epichlorohydrin at the C6single bondOH groups. The crosslinked cellulose was successfully oxidized with NaIO4 to form the crosslinked cellulose dialdehyde with an aldehyde content of 60%. The crosslinked dialdehyde cellulose was investigated as adsorbent for Congo red. The dye removal takes place via the Schiff-base formation as its two primary amino groups interact with the aldehyde groups of the CCDA. For the adsorption of CR by CCDA, 60 min, 37 °C, pH 4.0 and 25 ppm, respectively, were found to be the optimum time, temperature, pH and dye concentration. The kinetic and isotherm models reveal that dye uptake followed pseudo-second order kinetics and Langmuir isotherm. The adsorbent was reusable up to five repeat cycles and has the maximum retention capacity of 34.7 mg/g at optimized conditions. The modified cellulose, as reported here, has high adsorption capacity and is thus an efficient and economical alternative to the other expensive adsorbents employed for the removal of dye effluents from the industrial waste water before they are discharged into the water bodies.