Latex casting of macroinvertebrate fossils, when filling natural molds, produces a positive, or cast, reproduction of the organism. The use of latex molds to cast fossils in plaster or plastic materials will be discussed elsewhere in this volume. The purpose of this paper is to describe the preparation of latex casts for study and photography. The procedure for preparing a latex mold is essentially the same. Latex casts, carefully made, reproduce surficial detail with remarkable fidelity and a photograph of a whitened, stained-latex cast is often times indistingushable from a photograph of a well- preserved whitened body fossil.