Objectives We aimed to investigate whether uncomplicated type A intramural hematoma (IMHA) patients with type 2 diabetes mellitus (DM) who underwent a “wait-and-watch strategy” and tight glycemic control had similar clinical outcomes as patients without DM who received the same treatment strategy. Methods Between January 2010 and December 2016, uncomplicated IMHA patients with and without diabetes mellitus were included and were propensity score matched to improve balance between the two groups. Cox proportional hazard models were constructed to identify the specific factors associated with aorta-related mortality. The Fine-Gray model for the competing risk analysis was used to estimate the aorta-related and non-aorta-related mortality in different groups during the follow-up period. Results 109 IMHA patients were included in this study, and 66 patients were included after matching. Patients without DM experienced significantly more aorta-related adverse events (51.6% vs 13.3%, P=0.001) and reinterventions than patients in the DM group (29.0% vs 6.7%, P=0.023). Cox regression analysis revealed that a higher matrix metalloproteinase-9 level (hazard ratio [HR], 1.70; 95% confidence interval [CI], 1.39-2.09, P<0.001) and larger maximum aortic diameter (HR, 1.41; 95% CI, 1.11-1.80, P=0.005) were associated with higher aorta-related mortality. The competing risk analysis revealed a significantly higher aorta-related mortality during the follow-up period in the no DM group than in the DM group (36.4%; 95% CI, 11.6%-82.3%, P=0.0294). Conclusions Uncomplicated IMHA patients with DM (receiving the “wait-and-watch strategy” and tight glycemic control) may have a lower aorta-related mortality, and rates of aorta-related adverse events and reinterventions than the no DM group.