Underwater archaeology is the only branch of field archaeology that is dependent upon the conservation laboratory for its ultimate success. In fact, in underwater archaeology the activities of the conservation laboratory are considered to be a continuation of the field excavations with the recording of basic data along with the stabilization, preservation, and study of the recovered material being major objectives. Commonly used procedures for conserving ceramics, glass, bone, ivory, wood, leather, and the various metals are discussed. Observation and insights are presented on the applicability of the different processes for conserving various materials.