Background: Patients with type 2 diabetes have an increased risk of tachyarrhythmias and more frequently require implantable cardioverter defibrillators (ICD) than those without diabetes (No-DM). This study aims to investigate whether there is a difference in the indication, prognosis and complication rates for ICD-implantation between patients with and without type 2 diabetes in different ICD prevention groups. Research design and methods: This Swedish retrospective cohort study included patients with de novo ICDs implanted between 2010 and 2021. Data from six national registries were analyzed to compare type 2 diabetes and No-DM patients regarding indications, complications, and outcomes (major adverse cardiovascular events [MACE], all-cause mortality). Subgroup analyses compared type 2 diabetes and No-DM by primary (PP) or secondary prevention (SP) ICD indication, and within the type 2 diabetes and No-DM groups (PP vs. SP). Results: The study cohort consisted of 12,885 patients, including 2,843 with type 2 diabetes. Patients with diabetes had a mean age of 67.9 years and 85.4% were male, compared with 62.1 years and 78.1% among No-DM patients (both p < 0.0001). PP was more frequent in patients with type 2 diabetes (62.7%) than No-DM (54.4%, p < 0.0001). Ischemic heart disease was the most common etiology in both patients with/without type 2 diabetes (47.7% vs. 32.6%, p < 0.0001). Non-ischemic etiologies were more common in No-DM patients, e.g. dilated cardiomyopathy (15.3% vs. 17.5%, p = 0.007). Type 2 diabetes patients had a higher adjusted risk of all-cause mortality (Hazard ratio 1.95 [95% CI: 1.81–2.11]) and MACE (1.87 [1.71–2.05]), with a more pronounced risk in SP than PP. Infection rates were comparable between patients with type 2 diabetes and No-DM (1.1% vs. 1.3%). Conclusions: Patients with type 2 diabetes more often received ICDs for PP and ischemic indications than No-DM patients and had a worse prognosis despite similar one-year infection risk. This likely reflects greater comorbidity burden and diabetes-specific factors, indicating the need for tailored risk management strategies beyond device implantation in patients with type 2 diabetes.