Objective To evaluate the role of D-dimer and C reactive protein (CRP) in predicting inhospital death in acute aortic dissection (AD). Design A single-centre prospective study. Setting University hospital in China. Patients 114 patients with acute AD. Intervention Admission D-dimer and CRP concentrations were assayed. Main outcome measures To observe the association of D-dimer and CRP with inhospital death. Results Increased levels of plasma D-dimer (9.84 +/- 3.53 vs 4.28 +/- 1.99, P < 0.001), CRP (14.08 +/- 2.81 vs 11.18 +/- 1.85, P < 0.001) and aortic diameter (45.2 +/- 9.5 vs 40.3 +/- 6.0, p = 0.007) were found in dead patients compared with those survived. Moreover, plasma D-dimer concentrations in type A were higher than that in type B (6.51 +/- 4.11 vs 4.87 +/- 2.29, p = 0.013). Plasma D-dimer concentrations had positive correlations with CRP levels (r=0.527, P < 0.001) and aortic diameter (r=0.227, p = 0.015), and had negative correlations with the type of AD (r=-0.232, p = 0.013) and the time from onset (r=-0.264, p = 0.005). D-dimer and CRP levels and the type of AD were strongly associated with inhospital mortality. The OR and 95% Cl were 3.272, 1.638 to 6.535; 2.322, 1.134 to 4.757; and 0.126, 0.019 to 0.853, respectively. Furthermore, the sensitivity and specificity of D-dimer >= 5.67 mu g/mL in predicting inhospital death in acute AD were 90.3% and 75.9% (95% Cl 0.85 to 0.96), respectively. Moreover, the sensitivity and specificity of CRP levels >= 11.21 mg/L were 100% and 54.2%, respectively (95% Cl 0.74 to 0.89). Conclusions D-dimer >= 5.67 pg/mL, CRP >= 11.21 mg/L and type A acute AD were important risk factors and independently associated with acute AD inhospital death.