We report passivation of CdSe and CdSe/ZnS nanocrystals (NCs) with poly(N,N-dimethylaminoethyl methacrylate) ( PDMA) through a ligand exchange process. We present the results from various techniques that were used to verify that ligand exchange occurred, including H-1 NMR, P-31 NMR, and changes in solubility/ colloidal properties, hydrodynamic radius, and photoluminescence. We have examined the effect of polymer molecular weight on the surface passivation and quantum yields of the NCs. As additional evidence for the binding of the polymer to the surface of the NC, we were able to modify the polymer chemically to render the NC-polymer moiety water-soluble.