Endomyocardial fibrosis (EMF) is a disease of the rain-forest belt in Africa. There is general agreement as to its pathology in the acute phase, but this is difficult to diagnose clinically. The aetiology is still unknown although there are reports which suggest that eosinophilic endomyocardial disease may be the cause. Further studies are needed to define EMF in its acute stage and find out how chronic EMF evolves. A longitudinal study on young people with eosinophilia and a comparative study of two villages, one in an endemic zone and the other in a zone where EMF is uncommon, will also be helpful in identifying its cause. The most promising form of treatment at present is surgical.