E.I. du Pont de Nemours was incorporated in Delaware on February 26, 1902. After the incorporation T. Coleman du Pont was named president and his cousins Alfred I. du Pont and Pierre Samuel du Pont were named vice president and treasurer respectively. The next year the company began to experiment with new forms of organization and it created an executive committee on which both the corporate officers and departmental heads were represented. In the years before World War I the company began to systematically extend its control over the black powder and high explosives business. In 1907, the Justice Department filed suit claiming that E. I. du Pont de Nemours was in violation of the Sherman Antitrust Act. This litigation was settled in 1912 when the company divested itself of its high explosives business and the Atlas and Hercules Powder Companies were set up as independent entities.

After this reorganization Pierre Samuel du Pont was named chairman and chief executive officer. During the First World War the Du Pont Company became the largest supplier of munitions for the Allies. In the 1920s the company used its wartime profits to diversify, as it established its presence in the dyestuffs, paints, plastics, and cellophane markets. During this period the Du Pont Company invested its surplus capital in General Motors and by the mid 1920s it had obtained a controlling interest. In 1922 the company established a Fundamental Research Program as it set up laboratories devoted to physical, polymer, and organic chemistry. In 1937 the polymer chemistry laboratory, under the leadership of Dr. Wallace Carothers, developed nylon. After the Second World War nylon and the synthetic fibers that followed became the company's major source of revenue. During the Second World War Du Pont played an important role in the government's atomic energy program, as a number of its scientists worked on the Manhattan Project. The company also built atomic reactors at Oak Ridge, Tennessee, and Hanford, Washington. In 1948 the U.S. government again filed suit against the Du Pont Company. This time it claimed that its association with General Motors constituted an unlawful restraint of trade. This lawsuit was settled in 1962 at which time Du Pont was ordered to sell all its G.M. stock.

During the 1960s and '70s the company underwent several reorganizations and it slowly got out of the gunpowder and high explosives business in order to concentrate on textile fibers, biochemicals, plastics, and pharmaceuticals.