A short history of sludge characterization is given leading from sewage and sewage sludge treatment in former times to modern water and soil pollution control with resulting needs of sludge investigation and analysis. The progress in this field in the Federal Republic of Germany from the sixties till today is given as an example and the connections with the development in Europe with special regard to the concerted Action COST 68/681 of the Commission of the European Communities between 1972 and 1990 are described. Finally, the present situation is delineated which is determined by the work of the CEN Technical Committee 308 “Sludge characterization”, which was founded in May 1993.