Objectives COMMANDER-HF was a randomised trial comparing rivaroxaban 2.5 mg two times a day to placebo, in addition to antiplatelet therapy, in patients hospitalised for worsening heart failure with coronary artery disease and sinus rhythm. Patients with diabetes are at increased risk of cardiovascular events and therefore have more to gain. Methods and results In this post-hoc analysis, we evaluated the efficacy and safety of rivaroxaban in patients with (n=2052) and without diabetes (n=2970). The primary outcome was the composite of cardiovascular death, myocardial infarction (MI) or ischaemic stroke. HRs and 95% CIs with interaction analyses were used to describe event-rates and treatment effects. Patients with diabetes had a higher prevalence of cardiovascular comorbidities (eg, hypertension, obesity) and increased incidence of cardiovascular events. Adjusted HRs for events in people with versus without diabetes were 1.34 (95% CI 1.19 to 1.50) for the primary outcome, 1.21 (95% CI 0.84 to 1.75) for stroke, 1.51 (95% CI 1.14 to 1.99) for MI, 1.17 (95% CI 1.05 to 1.31) for heart failure hospitalisation and 1.06 (95% CI 0.56 to 2.01) for major bleeding. Rivaroxaban had no significant effect on event-rates in patients with and without diabetes (all interaction p values >0.05). Low-dose rivaroxaban was associated with an overall reduction in ischaemic stroke (HR 0.66; 95% CI 0.47 to 0.95), with no apparent subgroup interaction according to diabetes status (p-int=0.93). Conclusions In COMMANDER-HF a diagnosis of diabetes conferred higher rates of cardiovascular events that, with exception of ischaemic stroke, was not substantially reduced by rivaroxaban. Rivaroxaban was associated with reduced risk of ischaemic stroke for patients with and without diabetes. Trial registration number NCT01877915 ; Post-results.