Background: Depressed adults may show impairment in switching attention from one task to another. Rumination on negative thoughts is associated with the onset and persistence of depressive episodes. It is unclear if such mood-related ruminations are specifically associated with slowed ability in switching attention from one task to another. Method: Adolescents with current unipolar depression (n = 40) were compared with age and sex-matched controls (n = 38) on tests of attention and general cognitive abilities and completed the mood-related ruminative response style questionnaire. Results: Compared to controls, depressed participants were significantly slower at switching attention. There was no association between attentional switching and mood-related ruminations and both processes contributed to the likelihood of being depressed. Findings were not accounted for by slowness in reading and speaking, the effects of antidepressants nor being more careful on tasks. Conclusions: Depressed adolescents demonstrate dual deficits in mood-related ruminative thinking and attention. Further studies are needed to investigate whether higher ruminations are associated with attention impairments in emotionally-valent attentional switching tasks, and whether both processes precede the emergence of clinical disorder.