This publication deals with the use of phosphatic fertilizers to increase agricultural production in acid soils worldwide. It presents results obtained in a co-ordinated research project, which generated new information on the chemistry of soil phosphorus, tests for available soil phosphorus, phosphate nutrition of crops, evaluation of the agronomic effectiveness of Phosphate Rocks and recommendations on phosphorus fertilizers with particular emphasis on the utilization of indigenous PR sources. Due consideration was also given to environmental issues.