History and particular stages of the development of a domestic technol. for manufg. 2,4-Cl2C6H3CH2COOH (2,4-D) starting from a pilot plant in 1951-1955 and first com.prodn. (500 t/a) in 1960 to the today prodn. 8000 t/a of 2,4-D and its Me2N and Na salts were presented. The latest improvement of the chlorination of PhOH resulted in an increase in the chlorination selectivity from 89-90% to 95% and 2,4-D purity from 96% to 98%.