Glucose appetite in satiated, hungry, or thirsty rats was measured by ingestion of glucose and of saccharin solutions in free-choice tests. Type, concentration, and number of choices were determined with and without intragastric or intraperitoneal loads of metabolizable and nonmetabolizable sugars, urea, or NaCL. Taste and calories were evaluated as rate modulators in ad libitum feeding. Gastric distention, sweetness, and the chemical and osmotic properties of ingested glucose were evaluated as sources of satiety signals. The results indicate that: a) Taste is not a factor in ad libitum glucose intake; the caloric density of the solution is implicated. b) The satiety effect of intragastric glucose loads in independent of gastric distention or its potential osmotic effects. However, glucose intake may be related to the general state of hydration. c) The response to glucose and sucrose loads suggests the operation of a preabsorptive chemoreceptor system. The use of glucose appetite as a tool in the concomitant investigation of hunger and thirst is discussed.