Recebido em 6/12/00; aceito em 11/6/01 APLICATION OF GENETIC ALGORITHMS IN THE VARIABLE SELECTION IN MID INFRARED SPECTROSCOPY. SIMULTANEOUS DETERMINATION OF GLUCOSE, MALTOSE AND FRUCTOSE. Genetic algorithm was used for variable selection in simultaneous determination of mixtures of glucose, maltose and fructose by mid infrared spectroscopy. Different models, using partial least squares (PLS) and multiple linear regression (MLR) with and without data pre-processing, were used. Based on the results obtained, it was verified that a simpler model (multiple linear regression with variable selection by genetic algorithm) produces results comparable to more complex methods (partial least squares). The relative errors obtained for the best model was around 3% for the sugar determination, which is acceptable for this kind of determination.