This study reports the first U.S. population-level data on urinary concentrations of bisphenol A (BPA) and 4-tert-octylphenol (tOP) from the 2003–2004 National Health and Nutrition Examination Survey (NHANES). Urinary concentrations of BPA were detected in 92.6% of participants aged ≥6 years, with geometric mean (LSGM) concentrations varying by race/ethnicity, age, sex, and household income. Mexican Americans had significantly lower BPA concentrations than non-Hispanic whites and blacks, while females had higher concentrations than males. Children had higher BPA concentrations than adolescents, who in turn had higher concentrations than adults. Participants in the highest income category had the lowest BPA concentrations. For tOP, detection was lower (57.4%), with no geometric mean calculated due to low detection frequency. BPA exposure is primarily from food, with higher concentrations in children than in adults. BPA concentrations were higher in males than in females, though this difference was not statistically significant. The study highlights the widespread exposure to BPA in the U.S. population and the need for further research to identify exposure sources and assess health effects. The data suggest that BPA exposure varies by demographic and socioeconomic factors, emphasizing the importance of considering these variables in public health research and risk assessment. The findings provide a baseline for future studies to track changes in exposure trends over time.This study reports the first U.S. population-level data on urinary concentrations of bisphenol A (BPA) and 4-tert-octylphenol (tOP) from the 2003–2004 National Health and Nutrition Examination Survey (NHANES). Urinary concentrations of BPA were detected in 92.6% of participants aged ≥6 years, with geometric mean (LSGM) concentrations varying by race/ethnicity, age, sex, and household income. Mexican Americans had significantly lower BPA concentrations than non-Hispanic whites and blacks, while females had higher concentrations than males. Children had higher BPA concentrations than adolescents, who in turn had higher concentrations than adults. Participants in the highest income category had the lowest BPA concentrations. For tOP, detection was lower (57.4%), with no geometric mean calculated due to low detection frequency. BPA exposure is primarily from food, with higher concentrations in children than in adults. BPA concentrations were higher in males than in females, though this difference was not statistically significant. The study highlights the widespread exposure to BPA in the U.S. population and the need for further research to identify exposure sources and assess health effects. The data suggest that BPA exposure varies by demographic and socioeconomic factors, emphasizing the importance of considering these variables in public health research and risk assessment. The findings provide a baseline for future studies to track changes in exposure trends over time.