Insomnia has been associated with impairment in several cognitive domains such as attention, working memory, episodic memory and problem solving. Recent research has suggested that these neurocognitive deficits may be predicted by short sleep duration. Given the highly frequent comorbidity between insomnia and major depressive disorder, we aimed to assess neuropsychological performance in patients with major depression comorbid with insomnia with short sleep duration. Eligible subjects were outpatients with insomnia comorbid with major depressive disorder. To be included, patients were required to be female or male, 18 to 60 year-old, without comorbid psychiatric/sleep disorders, and without drug treatment. Participants were assessed with a structured psychiatric interview, 7-14 days sleep diaries, sleep and depression related scales, and two consecutive nocturnal polysomnographic recordings. They also completed neuropsychological test covering attention, memory, and executive functions. All patients gave their signed informed consent.On the basis of sleep duration reported in sleep diaries, patients were divided in short (< 6 hours) and normal (≥6 h) sleep duration. Major depressed patients with insomnia with short sleep duration (n=10) were not significantly different from patients with normal sleep duration (n=10) in age (40.9±15.4 vs 34.8±12.3, p=.34), gender (%female: 70 vs 50, p=.36), body mass index (25.9±3.7 vs 23.1±2.5, p=.06), insomnia severity index (20.8±4 vs 20.5±4.3, p=.87) and depression scores (23.3±6.2 vs 19.5±2.9, p=.09). The group with short sleep duration showed a worse performance on: d2 test of attention (Correct responses: 149.1±34.5 vs 200.7±41.3, p=.01; errors of commission: 5±4.6 vs 1.1±.9, p=.03; concentration performance: 143.8±38.7 vs 194.2±48.8, p=.03)); Tower of London test (Total moves: 99.6±12.8 vs 83.2±12.7, p=.01; additional moves (43.9±15.8 vs 24.9±13.5, p=.01) These preliminary results suggest that major depressed patients with insomnia with <6 hours of sleep duration present with impairment in selective and sustained attention, problem solving, and planning. Some of these neurocognitive deficits are similar to those observed in insomnia disorder with short sleep duration. NA