In the diagnostic work-up of socially unacceptable snoring (SUS) with or without a history suggestive of obstructive sleep apnoea syndrome (OSAS), information on the severity of the pathology as well as on local and general causative factors is needed. In part I of this study, we reported on the findings recorded in 380 patients by means of sleep registration. In this part, our emphasis is on analysis of the local contributing factors. In 340 of the 380 patients sleep endoscopy was performed to establish the level(s) of obstruction as accurately as possible. Sleep endoscopy was performed following artificial induction of sleep with midazolam and consisted in endoscopy and flexible nasopharyngoscopy and laryngoscopy. Although obstruction at the oropharyngeal level was often present, obstructions at lower levels or at multiple levels were also frequently found. In many cases sleep endoscopy showed obstruction at different level(s) than had been suspected on the grounds of ear nose and throat (ENT) investigation only. An obstruction at only one level was recorded in 35% of the patients (119), while 65% of patients (221) had multiple-level obstruction. The level(s) of obstruction could be well established by sleep endoscopy. We conclude that a diagnostic work-up involving a combination of sleep registration, sleep endoscopy, and analysis of general factors is worthwhile. Combining the results of these tests makes it possible to give individually tailored advice on treatment.