This study focuses on the long-term retention of basic mathematical techniques in a first-year calculus course, involving a sample group of engineering students at the University of Pretoria. The study investigates which and how much of the basic mathematical knowledge and rote skills acquired in the first year of study is retained after a further two years of study. A quantitative and qualitative investigations show that, in general, there is a significant decline in performance over a two-year period. There are, however, areas in which students still performed reasonably well after the elapsed period or even showed improvement. The research is of diagnostic value in that it assists course designers in determining what basic mathematical skills and knowledge are retained after a period of two years in their teaching approach to and emphasis of different topics. (Contains 1 table.)