The olfactory discrimination ability in a fruit-eating bat,Carollia perspicillata, was investigated. In a food-rewarded flight training procedure, four animals were taught to choose one of two odors simultaneously presented in a three-choice apparatus.Carollia chose the odor of ripe banana over that of unripe banana in a spontaneous choice test. With the same method, the bats significantly preferred undiluted banana odor compared to a dilution of 1∶ 10, but did not express a preference between undiluted and 1∶5 dilutions of ripe banana. In a series of reinforced choice tests, the positive stimulus (CS +) was the standardized odor of natural ripe banana. Prominent components of this complex odor were used as CS -, first in monomolecular form and later in combinations (odor cocktails) of increasing similarity to banana odor. In all these tests the bats easily discriminated the natural food odor from the artificial ones. Even a gas Chromatographic congruity of 57% between the major components of natural banana odor and an odor cocktail caused no impairment of the olfactory performance. The olfactory discrimination ability ofCarollia perspicillata supports the assumption that echolocating, frugivorous bats may use their sense of smell to find and select their food.