Duration, frequency, and temporal distribution of attacks have been objectively estimated in 11 SUNCT patients (3 women and 8 men). The mean age at the time of the study was 69 years (range 52 to 81). The duration of a total of 348 attacks was measured from videotape records, polygraphic tracings, or by stopwatch. The duration of attacks ranged from 5 to 250 seconds, with an unweighted mean of 61 seconds. Both frequency and exact timing of attacks were assessed in four patients who filled in a time chart with the exact onset of 585 consecutive attacks. The majority of attacks occurred during daytime, with a bimodal distribution; ie, morning and afternoon/evening peaks, and only a few attacks were noted at night (ie, 1.2% of the attacks). The unweighted mean frequency of attacks was 28 per day (range 6 to 77). Duration and timing of attacks in SUNCT syndrome may be of help in the differential diagnosis versus other disorders with the same localization, especially first division trigeminal neuralgia.