The occurrence of estrogens in the aquatic environment attracts increasing attention because of their strong endocrine disrupting potency. In the present work, concentrations of six estrogens including diethylstilbestrol (DES), estrone (E1), beta-estradiol (E2), estriol (E3), 17alpha-ethynylestradiol (EE2) and beta-estradiol 17-valerate (EV) in surface water and sediment sampled from three rivers in Tianjin area, northern China, were determined by gas chromatography-mass spectrometry (GC-MS). The concentrations of all six estrogens (Sigma6ES) ranged from 0.64 to 174 ng L(-1) in waters and from 0.98 to 51.6 ng g(-1) dry weight (dw) in sediments, and varied for each river. Among these estrogens, E1 was the most abundant and could be detected in all samples. DES and EV could be detected either in river water or in sediment, but in the concentration below 10 ng L(-1) and 10 ng g(-1) for water and sediment, respectively. The relationships between concentration of estrogens and organic carbon content in sediments and the relationships between sediment-water partition coefficient (logK(oc)) and octanol-water partition coefficient (logK(ow)) were examined. The results showed that the contents of the Sigma6ES correlated significantly with the contents of organic carbon (OC%). It indicated that sediments with high organic carbon were more likely to retain estrogens than those with lower organic carbon levels in the natural aquatic environment. Furthermore, the linear correlations between logK(ow) and logK(oc) were obtained for each river, which indicated that sediment-water partitioning of estrogens in three rivers could be predicted by their hydrophobic properties.