To determine the prevalence of vascular complications among inpatients with type 2 diabetes mellitus (T2DM) and factors independently associated with vascular complications in a tertiary care department in Ningbo, China, the authors conducted a cross-sectional study using an existing computerised medical records database. A total of 3370 adult patients with T2DM were admitted to this tertiary care department for the first time between 2012 and 2017. Patients were categorised as those (1) with at least one vascular complication, (2) with at least one microvascular complication, and (3) with at least one macrovascular complication. Over 5 years, the prevalence of vascular, microvascular, and macrovascular complications among inpatients with T2DM was 73.2%, 57.5%, and 51.4%, respectively. The odds of vascular, microvascular, and macrovascular complications increased with age and were higher in patients with hypertension. The odds of vascular and microvascular complications were higher in single, divorced, or widowed patients, patients with T2DM for a long time, and patients on advanced T2DM therapeutic regimen. The odds of vascular and macrovascular complications were lower in women. The odds of microvascular complications decreased with education. The odds of macrovascular complications were higher in smokers. In conclusion, in the tertiary care department, more than half of inpatients with T2DM had vascular complications, and factors independently associated with vascular complications were identified. The study findings could be used in future interventional studies to prevent and manage vascular complications among these patients.