Palatinose is a disaccharide molecule which can substitute sucrose as a sweetening agent. A microbial fermentation technology has been developed to produce palatinose. In order to verify the safety of palatinose products, we have performed 1) bacterial reverse mutation test using Salmonella typhimurium TA1535, TA1537, TA98 and TA100, and 2) in vitro chromosome aberration test using Chinese Hamster Lung (CHL) cell. In bacterial reverse mutation test, both palatinose and palatinose syrup did not induce any significant increase of $His^{+}$ revertants up to 10 mg/plate. In in vitro chromosome aberration test, palatinose and palatinose syrup also did not cause any significant increase of chromosome aberrant cells up to 5 mg/mL. These results suggest that palatinose products have no mutagenic potential in these in vitro mutagenicity tests.