Alkylphenol polyethoxylates (APEO), alkylphenols combined with ethylene oxide, are a class of nonionic surfactants. APEO have been widely used for industrial, agricultural and household applications, and are biodegraded to more persistent and estrogen-active products, namely, nonylphenol (NP), octylphenol (OP), butylphenol (BP), nonylphenol monoethoxylate (NP(1)EO) and nonylphenol diethoxylate (NP(2)EO). This study determined NP levels in commonly consumed foodstuffs to assess daily intake of NP in a Taiwanese population. This study analyzes 318 of samples from 25 types of commonly consumed foodstuffs in northern, central, southern and eastern regions of Taiwan and estimates daily intake of NP in 466 subjects. Moreover, daily NP intake for 3915 additional subjects was estimated by analyzing data from the Nutrition and health survey in Taiwan (NAHSIT). The foodstuff samples were analyzed for five alkylphenol compounds simultaneously by HPLC with fluorescence detection. Additionally, the average compositions of typical foods consumed in Taiwan were investigated. In combination with alkylphenol levels in these foodstuffs, daily intake of NP in Taiwanese was calculated. The average daily intake of NP for the 466 subjects was 28.04+/-25.32 microg/day. Estimated daily intake of NP, based on NP levels in this study as well as the NAHSIT data, was 31.40 microg/day. Rice was the most commonly consumed source of NP, the proportion was 21.46% among daily intake of NP and the following were aquatic products and livestock, which percentage were 17.97% and 17.38%, respectively. Additionally, oysters had the highest NP levels (235.8+/-90.7 ng/g) in four regions of Taiwan, followed by salmon (123.8+/-116.2 ng/g). This study suggested that the average daily NP intake in Taiwan is 4-fold and 8.5-fold higher than daily intake in Germany and New Zealand, respectively and rice was the major source of NP intake.