Strength and elongation have a great effect on slub yarn performance in production and usage. The main aim of this study is to determine the statistically significant descriptive parameters that have an effect on the breaking force and elongation of slub yarn using the full factorial design method. In addition, the effects of the significant parameters on the breaking force and elongation were investigated. Slub yarn samples were produced by using a ring spinning frame on which an original slub attachment was designed and mounted. After the samples were produced, dimensional measurements and image analysis were made. Then quality tests were applied to all samples and the results analysed. As a result, the parameters that have an effect on the breaking force of the slub yarn samples were obtained as the slub length, slub distance and base yarn count. The parameters affecting the breaking elongation of the slub yarn samples were obtained as the slub multiplier, base yarn count and twist coefficient. The relationship between the breaking force and elongation and the parameters selected have been explained by statistically significant regression equations. It is concluded that slub pattern parameters should also be considered for slub yarn performance.