This study examined the prevalence of irritability and social isolation in veterans with dementia, with and without depression. Participants were diagnosed with dementia and enrolled in a dementia care-coordination and support-service intervention. Participants were interviewed and underwent assessment with the 10-item Center for Epidemiologic Studies Depression scale, a Patient Strain Measure and the Short Blessed Test. In all, of 294 participants completing interviews, 77 (26.2%) were depressed and 107 (36.4%) endorsed irritability; mean social isolation score was 1.59 ± 1.96. Irritability was significantly more likely to be present in depressed versus nondepressed participants (P < .0001), but this relationship was moderated by dementia severity. The mean social isolation score was also significantly more elevated in depressed rather than nondepressed patients (2.82 ± 1.96 vs 1.15 ± 1.76, respectively). Conclusions: Depressed persons with dementia are significantly more likely to experience irritability and social isolation than those who are not depressed.