Background <p>Previous evidence regarding the associations of free triiodothyronine (FT3) and free thyroxine (FT4) with blood pressure (BP) were scarce. We aimed to explore the associations of FT3 and FT4 with BP (systolic BP [SBP], diastolic BP [DBP] and mean arterial pressure [MAP]) and examine the mediating roles of body mass index (BMI) and high–sensitivity C–reactive protein (hsCRP) in Chinese adults with coronary artery disease (CAD).</p> Methods <p>This hospital-based cross-sectional study included 4606 subjects. Serum FT3 and FT4 were measured.</p> Results <p>Among total populations, significant differences of 2.09 mmHg (1.73%) and 2.10 mmHg (1.73%) for SBP and 1.16 mmHg (1.32%) and 1.10 mmHg (1.25%) for MAP were observed between quartiles 4 and 1 of FT3 and FT4 in multi–variable analysis. Moreover, an intermediate FT3 concentration was associated with a higher risk of hypertension (HTN) (OR: 1.32, 95%CI: 1.03, 1.69). Similar positive association was also observed between FT4 and HTN prevalence. There was no significant association between FT3/FT4 ratio and BP (SBP, DBP and MAP). The mediating effects of BMI and hsCRP on “FT3 or FT4–BP” associations were not found among total populations in path analyses.</p> Conclusions <p>FT3 and FT4 were positively associated with SBP, MAP and HTN prevalence in Chinese adults with CAD. The “FT3 or FT4–BP” associations might not be mediated by BMI and hsCRP.</p>