Background: Neuropsychological impairment has been demonstrated in adults with depression. Whether depression arising during adolescence is associated with similar changes is unknown, We describe the neuropsychological functioning of a referred sample of medication-naive adolescent girls meeting criteria for a diagnosis of Depressive Episode (ICD-10). Methods: A cross-sectional study of 28 girls (ages 12-16); 14 with depression, 14 healthy controls matched for age, IQ and socioeconornic status. Neuropsychological testing was conducted using the CANTAB automated test battery. Results: Depressed adolescent girls showed performance deficits on visual memory tasks (Pattern Recognition, Delayed Matching to Sample and Paired Associates Learning), one measure of motor speed and on a test of Spatial Working Memory. Limitations: A restricted range of neuropsychological testing was performed on a female-only sample of modest size. Conclusions: Depressive episodes in adolescent girls are associated with neurocognitive deficits similar to those previously defined in adult populations and these impairments can be detected prior to exposure to psychotropic drugs. Neuropsychological impairment may be an important, neglected clinical feature in adolescent depression.