In a cell-surface engineering system established using the yeast Saccharomyces cerevisiae, novel, so-called arming yeasts are constructed that are armed with biocatalysts in the form of enzymes, functional proteins, antibodies, and combinatorial protein libraries. Among the many advantages of the system, in which proteins are genetically displayed on the cell surface, are easy reproduction of the displayed biocatalysts and easy separation of product from catalyst. As proteins and peptides of various kinds can be displayed on the yeast cell surface, the system is expected to allow the preparation of tailor-made functional proteins. With its ability to express many of the functional proteins necessary for post-translational modification and in a range of different sizes, the yeast-based molecular display system appears uniquely useful among the various display systems so far developed. Capable of conferring novel additional abilities upon living cells, cell-surface engineering heralds a new era of combinatorial bioengineering in the field of biotechnology. This mini-review describes molecular display using yeast and its various applications.