The purpose of this study was to investigate possible effects on undergraduate mathematics achievement of instructional uses of multiple representations. Four weeks of lessons on linear functions were developed, based on multiple representations supported by the use of electronic spreadsheets. The participants were 52 students enrolled in a college level algebra course. The control group received instruction strictly limited to the textbook and aligned with the course syllabus. The experimental group received an intensive treatment based on the use of spreadsheets and multiple representations, also parallel with the course content. The research took place during the fall semester of the academic year 2000-2001 at a private university in Ponce, PR. It was concluded that multiple representations of linear functions using spreadsheets enhanced achievement in mathematics in the course where this study was carried out. This was further documented by significant interaction effects for selected achievement sub-scores. It was also found that more positive attitudes toward certain aspects of mathematics could be expected as a result of using multiple representations of linear functions.