Background and objectives Fibroblast growth factor 23 (FGF23) regulates phosphorus and vitamin D metabolism. Elevated FGF23 concentrations are associated with cardiovascular disease events and mortality across a broad range of kidney function, but the predictors of FGF23 concentrations in the general population are unclear. Design, setting, participants, & measurements We examined cross-sectional associations of dietary and nondietary parameters with plasma FGF23 in 1261 participants of the Health Professionals Follow-up Study (mean age 64 ± 9, mean creatinine 0.9 ± 0.2 mg/dl, mean FGF23 64 ± 28 RU/ml). Results In multivariable-adjusted analyses, each 5-year increase in age was associated with 2.1 RU/ml higher FGF23, each 500-mg increase in phosphorus intake was associated with 3.4 RU/ml higher FGF23, and each 0.1-mg/dl increase in creatinine was associated with 3.4 RU/ml higher FGF23. Participants in the highest category of body mass index had 9.5 RU/ml higher FGF23 than those in the lowest, smokers had 17.1 RU/ml higher FGF23 than nonsmokers, and participants with hypertension had 6.0 RU/ml higher FGF23 than those without hypertension. With respect to biochemical parameters, higher parathyroid hormone, phosphate, uric acid, and triglyceride levels all were associated independently with higher FGF23 in models adjusted for age, creatinine, and other factors. In a subset of 748 participants with available data, some inflammatory biomarkers were associated independently with higher FGF23. Conclusions In community-dwelling adults with largely preserved kidney function, established cardiovascular risk factors and higher phosphorus intake were associated with higher FGF23. These results might explain the link between FGF23 and cardiovascular disease. © 2011 by the American Society of Nephrology.