Nickel ferrite-polyaniline nanocomposite has been prepared and characterized using different techniques. The prepared nanocomposite is used as an adsorbent for the removal of arsenic from aqueous solution of sodium arsenite. The effect of temperature on the equilibrium adsorption of As(rip from aqueous solution on nanocomposite has been investigated. Effect of pH (2-12), contact time (0-70 min), adsorbent dose (0.1-0.8) and initial metal ion concentration (10-30 mg/L) on the removal of As (III) have been studied. The maximum removal efficiency is found at pH 8.0. It is found that nickel ferritepolyaniline is a better adsorbent for removal of As(111) as compared to many others. The Langmuir adsorption isotherm model fits the data well and the process is found to be pseudo -second order. In order to understand the adsorption process, thermodynamic parameters such as Delta G degrees, Delta H degrees, and Delta S degrees, have been calculated.