Alteration of Denim Clothes for Re – Use : A Case Study on Female Students at Rajamangala University of Technology Phra Nakhon Rajamangala University of Technology Phra Nakhon The objectives of this research were (1) to design and alter old denim clothes for re-use (2) to study the female students’ behavior on purchasing used clothes and (3) to evaluate their satisfaction towards the altered old denim clothes. The stratified sample were 353 female students at Rajamangala University of Technology Phra Nakhon. The research tools were a questionnaire and 6 styles of original products. The data were analyzed by using a standard statistical method and reported as percentage means and standard deviation. Designing and alteration of old denim clothes include decorative addition. The total of 6 styles having an equal number of altered old shirts skirts and trousers were used in the study. It was found that 66.90 percent of female students purchased approximately 1 - 2 pieces of used clothes once every in 4 - 6 months. The most popular products were casual clothes namely jeans of which the satisfactorily pretty styles mainly affected their purchase decision. The result of the analysis on satisfaction towards the altered old denim clothes revealed that the students had strong satisfaction in every style.