Apparent sweetness, saltiness, and sourness in canned tomato juice was evaluated by trained judges categorized according to three levels of sensitivity. A method of paired-comparison constant-stimulus was used in which judges indicated the direction of the response as well as the magnitude of difference in taste intensity within each pair. The apparent sourness of citric acid was d epressed by both sucrose and sodium chloride.The sweetness of sucrose was reduced by citric acid, but enhanced by low levels of sodium chloride.Although the saltiness of sodium chloride was reduced by sucrose, it was significantly enhanced by acid. In the latter combination of taste stimuli, variability between judges was exceptionally large. Frequency of reversal of direction of response between duplicate pairs was greater among judges of low than among judges of high sensitivity.The extent to which the results agree with previous relationships with aqueous media and lima bean puree is discussed.