Sweetness and fruitiness of equisweet solutions of aspartame (APM), an aspartame + acesulfame-K blend (APM/AK) or sucrose were evaluated in binary (BIN) (sweetener and orange flavor) and tertiary (TER) (BIN and citric acid) systems by time-intensity (TI) methodology. Sweetener solutions adjusted to the viscosity of sucrose (APM* and APM/AK*) showed small inconsistent differences from their unthickened counterparts. In BIN systems, APM and APM* had the longest duration (DUR) of sweetness and fruitiness. In TER systems, APM* increased maximum intensity (MAX) and DUR of fruitness and S decreased sourness MAX and DUR relative to APM and APM/AK blends. Fruitiness MAX was perceived later than sweetness, whereas sweetness DUR persisted longer than fruitiness.