The United States of America vs. Carl Krauch, et al., also known as the IG Farben Trial, was the sixth of the twelve trials for war crimes the U.S. authorities held in their occupation zone in Germany (Nuremberg) after the end of World War II. IG Farben was the private German chemicals company allied with the Nazis that manufactured the Zyklon B gas used to commit genocide against millions of European Jews in the Holocaust.

The twelve trials were all held before U.S. military courts, not before the International Military Tribunal, but took place in the same rooms at the Palace of Justice. The twelve U.S. trials are collectively known as the "Subsequent Nuremberg Trials" or, more formally, as the "Trials of War Criminals before the Nuremberg Military Tribunals" (NMT). The IG Farben Trial was the second of three trials of leading industrialists of Nazi Germany for their conduct during the Nazi regime. (The two other industrialist trials were the Flick Trial and the Krupp Trial.)

The defendants in this case had all been directors of IG Farben, a large German conglomerate of chemical firms. The company had been a major factor already in World War I, when their development of the Haber–Bosch process for nitrogen fixation compensated for Germany's being cut off from the Chilean nitrate trade and allowed IG Farben to produce synthetic nitrate and extract and process nitrogen for use in agricultural fertilizer. (Nitrate is an important component for the fabrication of explosives such as gunpowder, dynamite or TNT.) In World War II, Degesch (42.5 per cent owned by IG Farben) was the trademark holder of Zyklon B, the poison gas used at some Nazi extermination camps. IG Farben also developed processes for synthesizing gasoline and rubber from coal, and thereby contributed much to Germany's ability to wage a war despite having been cut off from all major oil fields. The charges consequently centered on preparing to wage an aggressive war, but also on slave labor and plundering.

The judges in this case, heard before Military Tribunal VI, were Curtis Grover Shake (presiding judge), former Chief Judge of the Indiana Supreme Court; James Morris from North Dakota; Paul M. Hebert, dean of the Law School of Louisiana State University; and Clarence F. Merrell, a lawyer from Indiana, and friend of Judge Shake, as an alternate judge. The Chief of Counsel for the Prosecution was Telford Taylor. The indictment was filed on May 3, 1947; the trial lasted from August 27, 1947, until July 30, 1948. Of the 24 defendants arraigned, 13 were found guilty on one or the other counts of the indictment and sentenced to prison terms ranging from one and one half to eight years, including time already served; 10 defendants were acquitted of all charges. Max Brüggemann (Farben's chief legal advisor) was removed from the trial and his case discontinued on September 9, 1947, due to medical reasons.