By helping people visualize and experiment with mathematical phenomena, modem computing technologies have changed the way all people learn andwork. In schools, they can influence how mathematics is learned and taught not only by making calculations and graphing easier but by altering the very nature of what is important to learn. New problems, as well as new ways of investigating all problems, become accessible. Acknowledging the impact that technology has on mathematics and its uses, the NCTM’s Curriculum and Evaluation Standards for School Mathematics (1989) recommends that calculators and at least one computer for each classroom be available for students working individually or in groups. Representatives from all the National Science Foundation (NSF) secondary mathematics curriculum-development initiatives and from other significant reform projects were invited to comment on the role and use of technology in their curricula. This article presents the replies from three comprehensive secondary curriculum-development projects— Interactive Mathematics Program, Systemic Initiative for Montana Mathematics and Science, and University of Chicago School Mathematics Program—and from one smaller, more specialized project, Connected Geometry.