OBJECTIVE Cytidine-5'-diphosphocholine (CDP-choline) therapy is currently used to improve the consciousness level in patients with brain lesions and as a complement to levodopa therapy in Parkinson's disease. Recently, the substance has been shown to improve the visual acuity (VA) of both eyes of adults with amblyopia. This study aims at establishing whether Contrast Sensitivity (CS) and visually-evoked potentials (VEPs) also change after CDP-choline treatment. METHODS VA, CS, and VEPs were measured in a group of amblyopic volunteers (n = 10, mean age 24.8 years) before treatment with Neuroton (CDP-choline, 1 g/day intramuscularly [IM] for 15 days) and the day after termination of the same. CS was evaluated, using a forced-choice, automatic procedure (QUEST: Watson and Pelli, 1983). Steady-state VEPs were recorded in response to counterphased (8 Hz) sinusoidal gratings (2 c/deg) of different contrasts. RESULTS On average, after treatment, VA improved 1.4-1.5 lines in the amblyopic eyes and 0.4 lines in the normal eyes. CSs improved in both dominant and amblyopic eyes by about 3 dB. VEPs increased in amplitude (about 30%) and advanced in phase (about 0.2 pi rad). Amplitude and phase changes were not correlated. CONCLUSIONS Treating adult amblyopes with CDP-choline has the effect of improving their VA, CS and VEPs. Changes occur in both eyes, although to different extents, and resemble those previously reported for levodopa treatment.