Abstract: Objective To investigate concentrations of 1 hydroxy pyrene(1-OHP)in the urine of childrens younger than six years fromacity of south China.Methods Eighty urine samples were collected from the children in a kindergartens.After enzymic hydrolysis,the urine samples were preconcentrated and cleaned up by solid phase extraction.Then the urinary 1-OHP was determined by high performance liquid chromatography with fluore scence detection.Results The 1-OHP was detected in all urinary samples.The concentration of 1-OHP ranged from 0.10 to 1.64 mol/mol creatinine,and the concentration median was 0.38 mol/mol creatinine.The concentration of urinary 1-OHP was not only higher than those of the population in China,but also higher than that of those of the similar children in other countries.Over 75% of urine samples showed higher I-OHP levels than that of biologic exposure lmiits(BEL).Conclusion The children in the kinder garten of the city might have a higher risk of PAHs exposure.