Abstract: Theoretical values of ultrasonic velocity in four ternary liquid mixtures of 1-propanol, 1-butanol, 1-pentanol and 1-hexanol with TEA in n-hexane for different proportions have been evaluated using Nomoto`s Relation, Ideal Mixture Relation, Free Length Theory and Impedence Dependance Relation. Theoretical values are compared with experimental values and the Chi-square test for goodness of fit is applied to check the validity of the theories.