Between October 1974 and August 1997 in our Dizziness Clinic (n = 15,233), 2,523 patients were found to suffer from BPPV. All patients were assessed and followed up by the author. Patients (n = 337) having other ear or neurological diseases were excluded from this retrospective study. In 1644/2186 (75.21%) patients, the type of nystagmus was clinically identified in two opposite directions of gaze in the provocative head position. These patients were divided into two groups: i) idiopathic (n = 1,490) (no apparent cause); ii) post-traumatic (n = 154) (time of onset related to accident). It was found that in the idiopathic group men were older than women; women were more affected than men (2.3:1), and in the post-traumatic group there was no age difference between men and women; women and men were equally affected (1:1). In addition: i) patients were older in the idiopathic than the post-traumatic group. ii) BPPV of the posterior (PSC) was by far more prevalent than BPPV of the horizontal semicircular canal (HSC) in both groups, although there was no difference in prevalence between the two groups. iii) Bilateral involvement was more prevalent in the post-traumatic group. iv) All bilateral cases in both groups suffered from BPPV of the PSC. It is concluded that despite similarities, these two groups differ in a number of parameters. Thus the pathophysiology and the course of idiopathic vs post-traumatic BPPV may also be different.