[en] This study examines the design of a high precision dilatometer which utilizes laser interferometry as the basis for the length measurement system. The dilatometer is being designed for operation from ambient to 800⁰C using samples which require minimal preparation. Several interferometric techniques useful to dilatometry were reviewed from the literature. As a result of this review and establishment of performance criteria, a technical design is proposed. The optical design incorporates a two-frequency He--Ne laser with ac detection in a modified Michelson interferometer. A vertical sample/furnace configuration appears to offer a number of design advantages. Operational considerations and dilatometer development costs are also presented