This study investigated the relative sweetness of various sweeteners (tagatose, xylose, erythritol, sucralose, and enzyme treated stevia) in milk and instant coffee systems. Additionally, the effects of interactions with other ingredients on the sensory characteristics of milk and coffee were explored. In the case of a banana-flavored milk system, sucrose was added to a concentration of 5%, and the five types of sweetener were added to a concentration of equal sweetness to a 5% concentration of sucrose. For coffee systems, 5.9% sucrose level and sweeteners' concentration equivalent to this level was added. A generic descriptive analysis was performed using ten trained panelists. The results showed that the relative sweetness of all the sweeteners was identical to that identified in the aqueous system, except for stevia in the milk system and in the coffee system with added vegetable cream. For the black coffee system, the relative sweetness decreased for tagatose, erythritol and for stevia. Fat and vegetable cream significantly affected the sensory qualities of milk and coffee, respectively.