Costume is a very important communication tool for understanding the characters on the theatre stage and the nature of the production. Costume, which is described as a silent interpreter on stage, does not only give information to the audience, but also enhances the visual effect on the performance, thus supports the actor. Costume’s other design applications, which form the theatre stage, and putting forward the relationship between the director and the actor are important for creating a consistent and effective scene.The aim of this study is to determine the costume design process for theatre stage and to reveal costume’s relationship with other creative processes and people. Case method is used in the research. The sample of the study is the costume design process in Fermanlı Deli Hazretleri play, which was staged on Konya State Theatres in 2016-2017 theatre session. Purposeful sample technique, which is one of the judgmental sampling techniques, is used to determine the sample. The data for the research is recorded by using the interview form developed by the researcher. The result of the study is that costume, scenery and lighting are regarded as a whole, and to achieve the most creative and effective results, creative team must work together under the guidance of the director. Based on the findings, suggestions were made for designers who wish to design costumes.