Determination of the instability of air-jet textured yarns is a very important aspect of their quality characterization. To overcome this problem many researchers have suggested different techniques, however none has been accepted as a standard method. Among all the methods, that suggested by Demir et al. takes attention, since it was improved after investigating the advantages and disadvantages of most of the techniques in use. Recovery from strain measurements are commonly used to get information about fiber molecular structure. In this study, instability of air-jet textured yarns was investigated by using both Demir's instability test method and recovery from strain measurements. It was observed that Demir's method is a practical and reliable way to compare the instability of air-jet textured yarns produced from the same raw material. For comparing different materials it was more beneficial to use recovery from strain measurements.