Abstract: To investigate the characteristics of residential indoor and personal exposure to PM_2.5, samples of two types of PM_2.5 for elderly participants were collected in an elderly community in Tianjin during summer (from June 13^th to July 2^nd) and winter (from November 30^th to December 12^th) in 2011. Subsequently, chemical compositions were analyzed. The results showed that the mass concentration of indoor PM_2.5 was (138±103) μg/m³ in summer and (173±136) μg/m³ in winter, with significant seasonal differences (P<0.05). The indoor PM_2.5, SO₄^2- and OC mass concentrations were significantly higher in winter than those in summer (P<0.05), due to coal combustion for domestic heating in winter. The contributions of indoor sources to some of the indoor PM_2.5 compositions (Al, Ca, and Cd) were higher in winter than in summer. The mass concentrations of personal exposure to PM_2.5 were significantly correlated with those of indoor PM_2.5 in both summer and winter, and were not significantly different between the two types of PM_2.5 (P>0.05). In addition, the coefficient of divergences (COD) was used to compare the chemical compositions between indoor and personal exposure to PM_2.5 based on time activity patterns for elderly participants. The results showed that the COD of indoor-personal exposure PM_2.5 was 0.34±0.10 and 0.37±0.12 in summer and winter, respectively. The percentage of indoor-personal exposure samples with COD values over 50% in winter was higher than in summer. The ratio of OC/EC of indoor PM_2.5 was similar with that of personal exposure to PM2.5 in both summer and winter, indicating similar sources of carbon materials for indoor and personal exposure to PM_2.5.