We conducted a quantitative electroencephalographic (QEEG) and autonomic assessment of panic disorder (PD). The study samples comprised 52 individuals meeting DSM-IV criteria for PD (with or without agoraphobia) and 104 age-, gender-, and handedness-matched controls. EEG data were acquired from 16 scalp sites during resting eyes-open (REO) and eyes-closed (REC) conditions, and spectral power was assessed within 4 frequency bands: theta, alpha-1, alpha-2, and beta. The main findings were an overall reduction of spectral power in PD, compared to controls (Group main effect, p= .011), which was most apparent during REC (Group Condition interaction, p= .014), and within the alpha-1 frequency band (8-11. Hz; Group Band interaction, p= .014). Alpha-1 desynchronization occurs in response to increases in non-specific information processing, and aspects of attention such as alertness. Other findings were region-specific alterations of spectral power at frontal and temporal scalp sites, including a frontal alpha-1 asymmetry (R < L power) during REC in patients, but not controls. Findings for concomitantly-recorded autonomic measures included elevated heart rate, lower heart rate variability, and reduced rate of decrement of skin conductance level in patients, compared to controls. Finally, analyses examining the within-subjects relationship of central and peripheral function measures showed a differential pattern in patients and controls. Possible causes of these disturbances of brain and body function 'at rest', such as patients' ongoing automatic and strategic engagement with multiple disorder-related threat cues, including somatic variability and the testing environment, are discussed.