Electron probe microanalysis, x-ray diffusion and microscopic examination were conducted on bone material from several archaeological sites in order to identify post-burial inclusions which, if present, may effect radiocarbon dating of bone. Two types of inclusions were identified: (1) precipitates from ground water solutions, and (2) solid intrusions. The first type consists of calcite, pyrite, humates? and an unknown material. The second type includes quartz grains, hyphae, rootlets, wood, and charcoal. Precipitation of calcite in a macro-molecular level in bone may lead to erroneous dating of bone apatite if such calcite was not removed completely. A special technique, therefore, must be employed to remove calcite completely. Hyphae and rootlets also are likely to induce errors in radiocarbon dating of bone collagen. These very fine inclusions require more than hand picking.