From 1960 to 1990 persistent frenulum praeputii was found to be the cause of impotentia coeundi in 49 young boars. The findings obtained from clinical investigations are described and the anatomical peculiarities of persistent frenula are dealt with in detail. In 71.4% of the cases the impotentia coeundi could be overcome by operative removal of the existing connective bands. Genealogical studies revealed a special disposition in pigs of the breed Edelschwein without any definite involvement of genetic factors.