We developed an original analytical method for monitoring five estrogens, nine androgens, nine progestogens, six glucocorticoids, and one mineralocorticoid in one water sample using liquid chromatography-electrospray tandem mass spectrometry, and then 45 river, 13 discharging sites, and 4 composite effluent samples were analyzed to reveal their occurrence and sources in urban rivers. Of the 45 river samples, androgens were the dominant steroids detected (total concentrations up to 480 ng/L), followed by glucocorticoids (up to 52 ng/L), progestogens (up to 50 ng/L, and estrogens (up to 9.8 ng/L). The summed concentration for each class of detected hormones in 13 discharging site samples was higher than that in river samples, up to 1887 ng/L for androgens, 390 ng/L for glucocorticoids, 75 ng/L for progestogens, and 25 ng/L for estrogens. A principal component analyses with multiple linear regression based on the profiles of all target compounds was applied to identify the source apportionment and to predict the contribution from different sources. It was found that 62.7% of the mean summed hormones were contributed by freshly discharged untreated sewage, 29.4% by treated sewage and/or naturally attenuated untreated sewage, and 7.9% by an unknown source, possibly pharmaceutical manufacturing plants.