Binding of a HEUR (hydrophobic ethoxylated urethane) associating polymer (AP) (MW 51000, C16 hydrophobic end caps) to polystyrene latex (diameter 168 nm) was investigated by a combination of NMR diffusion, relaxation time, and adsorption measurements. Adsorption of the HEUR AP to the latex particles could be quantified by H-1 NMR using a depletion method and could be described by a Langmuir isotherm. The latex-bound HEUR AP exhibited a spin-lattice relaxation time (T-1) identical to that measured in bulk solution. The spin-spin relaxation time (Ttl of the adsorbed HEUR AP was, however, much shorter than that measured in bulk solution, an effect attributed to the slow rotational tumbling of the large latex particles. Diffusion of the free HEUR AP remaining in solution upon addition of latex was enhanced due to depletion of the polymer concentration in the bulk solution and the consequent breakup of the associated network. Diffusion of the latex-bound HEUR AP reflected the diffusion of the latex particles themselves.