Pilonidal sinus disease (PSD) is common among young adults and occurs more often in men than in women (3:1). Pilonidal derives from pilus (“hair”) and nidus (“nest”) and literally means nest of hair. In practice, PSD is mostly defined as the presence of one or more pits or sinus cavities in the sacrococcygeal area that often contain hair and are prone to infection and abscess formation. The etiology of PSD has been discussed for more than two centuries. Our interest in the etiology of PSD was sparked after two patients visited our outpatient clinic with surprising findings in their pilonidal cavities. These findings motivated us to review the literature to better understand the etiology of this disease. Ten articles contained original research on the etiology of PSD in the IGF and were finally included for this review.