This study aims to investigate how a teacher-researcher and her students react to the use of transparencies, the use of Powerpoint slides and the gradual change from the use of transparencies to Powerpoint slides as visual aids in an English communication skills course. The teacher's reactions to the use of the two kinds of visual aids were recorded in teacher journals. The students' opinions on the effectiveness of the use of transparencies and Powerpoint slides were collected through a questionnaire and interviews. Through the triangulation of the questionnaire, interview and journal data, the impact of the use of transparencies and Powerpoint slides on the parties involved, the problems that emerged during the process of change, and the possible solutions to the problems were investigated. The educational theories behind the use of transparencies and Powerpoint slides, the pedagogical advantages and disadvantages of using each of them to aid teaching and the pedagogical implications for the choice and use of the two kinds of visual aids will be discussed.