Abstract： Objective To investigate the levels of lanthanum,cerium,praseodymium,and neodymium in the blood,urine,and hair samples from residents in the rare earth mining area of a city in China,and to provide a scientific basis for the control of rare earth pollution and the protection of population health.Methods A total of 147 residents who had lived in the rare earth mining area of a city for a long time were selected as the exposure group,and 108 residents in Guyang County of this city who lived 91 km away from the rare earth mining area were selected as the control group.Blood,urine,and hair samples were collected from the residents in both groups.Inductively coupled plasma mass spectrometry was used to determine the content of lanthanum,cerium,praseodymium,and neodymium in blood,urine,and hair samples.Results In the exposure group,the median levels of lanthanum,cerium,praseodymium,and neodymium were 0.854,1.724,0.132,and 0.839 μg/L,respectively,in blood samples,0.420,0.920,0.055,and 0.337 μg/L,respectively,in urine samples,and 0.052,0.106,0.012,and 0.045 μg/g,respectively,in hair samples.The exposure group had significantly higher levels of the four rare earth elements in blood,urine,and hair samples than the control group(P＜0.01).Conclusion The residents in the rare earth mining area of this city have higher content of lanthanum,cerium,praseodymium,and neodymium in blood,urine,and hair than those in the non-mining area;the content of cerium is highest,followed by lanthanum,neodymium,and praseodymium.