The association between high-density lipoprotein cholesterol(HDL-C) and mortality in patients with acute aortic dissection(AAD) is unclear. From January 2007 to January 2014, a total of 928 consecutive AAD patients who were admitted within 48 h after the onset of symptoms were enrolled in the study. Patients were divided into two groups according to whether serum HDL-C level was below the normal lower limit or not. The Cox proportional hazard regression model was used to identify the predictive value of HDL-C for in-hospital mortality in patients with AAD. As compared with normal HDL-C group(n=585), low HDL-C group(n=343) had lower levels of systolic blood pressure and hemoglobin and higher levels of leukocyte, alanine aminotransferase, blood glucose, blood urea nitrogen, creatinine and urea acid. Low HDL-C group had significantly higher in-hospital mortality than normal HDL-C group(21.6% vs. 12.6%, log-rank=10.869, P=0.001). After adjustment for baseline variables including demographics and biologic data, the increased risk of in-hospital mortality in low HDL-C group was substantially attenuated and showed no significant difference(adjusted hazard ratio, 1.23; 95% confidence interval, 0.86–1.77; P=0.259). Low HDL-C is strongly but not independently associated with in-hospital mortality in patients with AAD. The association between high-density lipoprotein cholesterol (HDL-C) and mortality in patients with acute aortic dissection (AAD) is unclear. From January 2007 to January 2014, a total of 928 consecutive AAD patients who were admitted within 48 h after the onset of patients were enrolled in the study. Patients were divided into two groups according to whether serum HDL-C level was below the normal lower limit or not. The Cox proportional hazard regression model was used to identify the predictive value of HDL-C for in --hospital mortality in patients with AAD. As compared with normal HDL-C group (n = 585), low HDL-C group (n = 343) had lower levels of systolic blood pressure and hemoglobin and higher levels of leukocyte, alanine aminotransferase, Blood glucose, blood urea nitrogen, creatinine and urea acid. Low HDL-C group had significantly higher in-hospital mortality than normal HDL-C group (21.6% vs. 12.6%, log-rank = 10.869, P = 0.001) adjustment for baseline variables including demographi cs and biologic data, the increased risk of in-hospital mortality in low HDL-C group was substantially attenuated and showed no significant difference (adjusted hazard ratio, 1.23; 95% confidence interval, 0.86-1.77; P = 0.259) -C is strongly but not independently associated with in-hospital mortality in patients with AAD.