Laser remote sensing has proved to be a mature technique in many scientific, military, and civilian fields. In particular, laser range-finders are widely applied in non- contact measurements of distances. In the framework of the project ARCHEO, funded by the Italian Ministry for Universities and Scientific and Technological Research, we have developed GEOLIDAR, a miniaturized laser range-finder that provides useful information for archaeological excavations. More precisely, GEOLIDAR performs volumetric characterizations of underground cavities, such as buried tanks, temples, and tombs. A coring machine bores a small- diameter hole up to the cavity where GEOLIDAR is let down and executes a motor-driven 3D scan. Operation and acquisition are fully controlled by a user-friendly computer interface.