This research characterized the time-intensity (TI) profiles of monosodium glutamate (MSG), disodium 5′-inosinate (IMP), and disodium 5′-guanylate (GMP). Twenty subjects rated total taste intensity of single solutions of 2.5, 5 and 10 mM MSG, 0.63 and 2.5 mM IMP and GMP, and some of their mixtures, using the TI method. The profiles generated were atypical of other taste modalities. Time to maximum intensity waslong (16–20s), followed by a plateau at maximum intensity, and a persistent aftertaste (50–96s duration). Maximum intensities of the samples varied (p < 0.001), with mixtures of 10 and 5 mM MSG with 2.5 mM IMP or GMP yielding the highest intensities. Similar differences were found for total duration and area under the curve. These results indicate that flavor potentiators may increase total flavor during consumption. Synergism between flavor potentiators was demonstrated.