The peste des petits ruminants (PPR) is proving to be a disease which has an increasingly significant economic impact on a number of countries in Africa and the Middle East, and possibly also on the Indian sub-continent. The antigenic relationships which exist between the PPR and rinderpest viruses pose problems for diagnosis which complicates rinderpest control and eradication programmes. Progress has recently been made in regard to diagnosis (specific nucleic probes and monoclonal antibodies), as well as control (homologous vaccine). International legislation remains to be established and epidemiological surveys should be conducted in order to determine the exact geographical distribution of the disease.