We aimed to describe admission rates and outcomes of hospitalized people with Alzheimer’s disease (AD) or senile dementia stratified by type 2 diabetes (T2D) in Spain, 2004 to 2013 (N = 541 858, 143 501 [26.5%] of whom had T2D). We excluded alternative causes of dementia. Hospitalization rates were higher in people with T2D (130.5 vs 91.5 cases/105 people). People older than 84 years and comorbidity increased over time. Crude inhospital mortality (IHM) decreased over time both in people with and without T2D (all P values <.001). Time trend analyses, 2004 to 2013, showed an overall adjusted incidence rate ratio (95% confidence interval [95% CI]) of hospitalization of 1.41 (1.40-1.42) for T2D (men, 1.32 [1.30-1.33]; women, 1.46 [1.45-1.48]). In logistic regression analyses, IHM decreased over time (odds ratio, OR [95% CI] = 0.97 [0.96-0.98]) and T2D was not associated with a higher IHM (OR [95% CI] = 0.99 [0.98-1.01]). In conclusion, admission rates were higher in patients with T2D. Inhospital mortality decreased over time. Diabetes did not predict IHM in patients with AD or senile dementia.