The perceived intensity and quality of binary odor mixtures are studied in relation to how their components are perceived when presented separately. Subjects judged the perceived intensity and quality of 6 concentrations of pyridine, 6 concentrations of n-butanol, and their 36 possible combinations. The results show that the perceived intensity of the mixture can be predicted from the perceived intensity of its components presented separately (RA and RB) by the Euclidian arithmetic model. The maximum probability of identifying a mixture as a "mixture" is reached when RA and RB are equally strong. An interaction model for mixtures that relates perceived intensity and quality is presented and tested. The test reveals that both the perceived intensity of a mixture and the probability that it will be identified as the one or the other component can, by a simple interaction model, be successfully predicted from RA and RB.