Introduction. Mildly increased bilirubin concentration has a protective effect on oxidative stress–related diseases. However, it remains unknown whether elevated circulating bilirubin is associated with longer telomere length. The aim of this cross-sectional study was to examine the association between total bilirubin concentration and telomere length. Methods. We used the data from the National Health and Nutrition Examination Survey (NHANES) 1999-2002. The multivariable linear regression model was used to examine the association between total bilirubin concentration and telomere length. The nonlinear relationship was analyzed using a generalized additive model with the smoothing plot. Results. A total of 7818 participants with a mean age of
49.20
±
18.82
years were included. Compared with the lowest concentration of total bilirubin (Q1), the highest quartile of total bilirubin concentration was associated with longer telomere length in male (
β
=
0.04
, 95 CI%: 0.00, 0.07,
P
=
0.024
) and female (
β
=
0.04
, 95 CI%: 0.02, 0.04,
P
=
0.002
). Furthermore, an inverted U-shaped relationship between total bilirubin and telomere length was found. On the left of turning points (
total
bilirubin
<
0.5
mg
/
dL
), total bilirubin concentration was positively associated with telomere length (
β
=
0.23
, 95 CI%: 0.14, 0.32,
P
<
0.001
). However, the association between total bilirubin concentration and telomere length was not significant (
β
=
0.01
, 95% CI: -0.01, 0.04,
P
=
0.346
) above the turning point. Conclusion. This is the first evidence based on a nationally representative survey demonstrating a positive and nonlinear association between total bilirubin concentration and telomere length. Future large-scale prospective studies are warranted to confirm our findings.