Objective and subjective sleep and awakening quality as well as daytime vigilance of insomniac patients with generalized anxiety disorder (GAD) were investigated, as compared with normal controls. Forty-four outpatients (25 females, 19 males), aged 24–65 (mean 43) years, diagnosed with non-organic insomnia (ICD-10: F 51.0), related to mild GAD (F 41.1), with a Hamilton anxiety (HAMA) score of 22 ± 6 and a Zung self-rating anxiety (SAS) score of 37 ± 6 were included. After 1 adaptation night, sleep induction, maintainance and architecture were measured objectively by polysomnography, subjective sleep and awakening quality were assessed by self-rating scales and visual analog scales, objective awakening quality was measured by a psychometric test battery, and diurnal tiredness was measured by a 3-min vigilance-controlled EEG (V-EEG) and a 4-min resting EEG mapping. In polysomnography patients demonstrated – as compared with normals – significantly increased wake time during the total sleep period and more early-morning awakening, decreased total sleep and sleep efficiency. Subjective sleep quality was deteriorated as well, as were well-being, drive, mood, and wakefulness in the morning. In noopsychic performance, GAD patients did rather well in attention, concentration, attention variability, and numerical memory, while fine-motor activity and reaction time were deteriorated. In psychophysiology, critical flicker frequency was decreased in the morning, while muscle strength, blood pressure and pulse rate showed no differences. EEG mapping during the late morning hours (10.00–12.00 h) demonstrated hypervigilance in the V-EEG, while in the resting recording an increased sleep pressure was detected. The latter was correlated significantly to the SAS score, but less so to the observer-rated Hamilton anxiety score. Our findings suggest that CNS hypervigilance and hyperarousal, as actual symptoms of GAD, lead to nocturnal insomnia, which in turn may cause – as a consequence of sleep pressure not slept off -diurna