On using common Lisp for scientific computing. Lisp is a very flexible and powerful language, but up to now it has not been used intensively for applications in scientific computing. The main reason is the prejudice that Lisp is slow. While this prejudice may have been true in early stages of Lisp’s history, it is not really true today. Furthermore, the virtues of Lisp are becoming more and more important. In this contribution, we support this point of view: first, by comparing the efficiency of BLAS routines written in C an Common Lisp and second, by discussing the recently developed toolbox FEMLISP for solving partial differential equations with finite element methods and multigrid.