Amino acids as the building blocks of proteins are presumed to be important in food selection and species with a low protein diet need to be able to maintain their protein requirements. The purpose of this study was to determine taste preference thresholds for six L-amino acids in spider monkeys, Ateles geoffroyi. Using a two bottle preference test, four spider monkeys were tested for their ability to discriminate between various concentrations of six L-amino acids and plain water until they reached their taste preference thresholds. The spider monkeys were able to significantly discriminate concentrations as low as 2 mM L-alanine, 10 mM L-aspartic acid, 2 mM L-glutamic acid, 0.2 mM L-lysine, 2 mM L-serine and 20 mM L-valine from the solvent. The taste preference thresholds were all in the range of humans except L-aspartic acid which indicates that spider monkeys are as good as humans at sensing these amino acids.