Zerovalent iron nanoparticles (NZVI) are an emerging technology for ground water remediation of dense nonaqueous phase liquids (DNAPL). Polymeric surface coatings are required for mobility in the subsurface and can afford the particles an affinity for DNAPL. The ultimate fate of the particles depends in part on the stability of the surface coatings. One often observes effectively irreversible adsorption of high molecular weight polymers on solid surfaces. This study reports desorption rates of commercially available polyelectrolytes, including polyaspartate (MW=2.5k and 10k), carboxymethyl cellulose (MW=90k and 700k), and polystyrene sulfonate (MW=70k and 1M) from NZVI used for in situ degradation of DNAPL in groundwater. The initial adsorbed masses of polyelectrolyte ranged from 1.5 to 4.0 mg/m². For a given polyelectrolyte, the adsorbed mass was independent of molecular weight. Desorption was very slow, with less than 30% of each polymer desorbed after 4 months. Quartz crystal microbalance (QCM) data confirmed the presence of polymer on the particle surfaces by comparing the attachment of bare and modified particles to a silica surface. Transport experiments also indicate that the polymer coating is still on the surface of NZVI. Based on these results, polymer modified nanoparticles will potentially remain mobile for long times after they are injected into the subsurface. Other factors that might affect coated NZVI fate, especially the potential for microorganisms to degrade the polymer coatings, must still be evaluated.