The antiamnesic activity of nerve growth factor (NGF) in various medicinal forms [aqueous NGF solution with and without polysorbate-80 (PS-80) additives, NGF adsorbed on poly(butyl) cyanoacrylate (PBCA) nanoparticles with and without PS-80 coating] has been studied in rats with model amnesia induced by scopolamine (2 mg/kg, s.c.). The antiamnesic activity was evaluated by the ability of subsequently introduced drugs (5 microg NGF per animal, i.p.) to inhibit the amnesic action of scopolamine as manifested by retrieval of the passive avoidance reflex (PAR) learned using the Lafayette Instruments USP system 30 min after drug injection. The PAR memory trace was evaluated as an increase in the latent time before visiting the dark compartment 24 h after drug injection. In the untreated amnesia control group, the scopolamine amnesia was manifested by the absence of any increase in the PAR latent time. In the form of an aqueous solution, NGF did not inhibit the scopolamine-induced amnesia. NGF adsorbed on uncoated PBCA and in the form of solution with PS-80 produced an antiamnesic action manifested by a reliable increase in the PAR latent time as compared to that in the untreated control group. NGF adsorbed on PBCA nanoparticles coated with PS-80 not only exhibited a significant antiamnesic effect, but even stimulated the cognitive function and increased the PAR latent time above the value in the learned control group.