Teeth and blood samples reflected different jaw types, covered a wide age range, and were from both sexes. Some deciduous teeth were also collected from school children. Only teeth extracted for orthodontic purposes or those with no apparent damage to dental tissues were analyzed. ABO blood groups were successfully determined from dentine, pulp, and cement samples, whereas only dental pulp could be typed for different isozymes. Studies of the persistence of these genetic markers in teeth stored at room temperature showed that ABO blood groups were the most stable, followed by PGM1 and ADA isozymes, whereas CA-II isozymes were the least stable. It was determined that, because teeth can withstand the vagaries of the environment and retain activities for serogenetic markers and DNA polymorphisms longer than blood stains or other body tissues, the analysis of teeth can be important in personal identification. 26 references and 5 tables