Purpose: Studies regarding death risk factors of disseminated intravascular coagulation (DIC) patients were limited. Therefore, we conducted this study to investigate whether the serum anion gap (AG) was independently related to all-cause mortality of DIC patients. Methods: We used the data from Medical Information Mart for Intensive Care III version 1.4 (MIMIC-III v1.4). A total of 2,654 DIC patients were included. The main outcomes were in-hospital, 30-day, and 90-day all-cause mortality. The AG was measured upon ICU admission and its association with mortality was evaluated using the Cox proportionalhazards regression model. The generalized additive model and the smooth curve fitting were introduced to examine the non-linear association. Results: After adjusting for potential covariates, the in-hospital, 30-day, and 90-day allcause mortality were positively correlated with AG. The hazard ratio (HR), confidence intervals (CI), and P were 1.05 (1.04-1.07) <0.0001, 1.06 (1.04-1.07) <0.0001, and 1.05 (1.03-1.07) <0.0001, respectively. We did not find an obvious non-linear relationship between AG and in-hospital, 30-day, and 90-day mortality, which indicated that the association between AG and all-cause mortality of DIC patients was nearly linear. Conclusion: Serum AG is positively related with all-cause mortality in DIC patients.