Abstract: Computer algebra systems or software that can manipulate mathematical objects numerically, symbolically and graphically are poised to change the way teachers teach and students learn mathematics. In this paper, to address this change, the development of the Computer Algebra System Attitude Scales, through adapting a widely used computer attitude scale and writing new items, is described. A field test of this instrument in assessing the attitudes of 50 pre-service teachers toward computer algebra system (CAS) upon completion of a CAS-related module requirement of their teacher training programme. The results of the field testing are also discussed.