Uniform chitosan nanoparticles have gained interest in recent years for their wide variety of applications. This study presents an optimum condition for preparation of uniform size of chitosan nanoparticles (CSNPs) from waste shrimp shells based on their evaluation by SEM study, and other spectrometric methods were used to characterize their adsorptive property. Initially, chitosan was extracted from shrimp shells. Then CSNPs were produced from the extracted chitosan by a self-modified ionotropic gelation method. The characteristic features of prepared chitosan and chitosan nanoparticles were investigated by determining molecular weight, degree of deacetylation, particle size, surface morphology, crystal structure, etc. using FTIR, XRD, and SEM-EDX analysis. Optimal conditions were selected based on the SEM evaluation of the uniform particles size (in a short range of 13–20 nm in diameter) of CSNPs. The adsorption efficiency of chitosan nanoparticles was investigated using acid red 1 (AR1) as a model adsorbate, and the effect of operational parameters such as contact time, dye concentration, temperature, and solution pH were investigated. Batch adsorption kinetics of AR1 on CSNPs follows pseudo second order kinetic equation. This implies the adsorption could be controlled by chemisorption, whereas the adsorption isotherms follow the Langmuir equation. The adsorption capacity of CSNPs, calculated from Langmuir equation, was found 243.9 mgg-1 at 35 °C which escalated with increase in temperature suggesting endothermic adsorption. Based on these results, the CSNPs prepared from shrimp shell waste can be used as high potential and efficient adsorbent to remove AR1 from waste water.