Ramzi Yousef is found guilty of masterminding the 1993 World Trade Center bombing.

The 1993 World Trade Center bombing was a terrorist attack on the World Trade Center in New York City, U.S., carried out on February 26, 1993, when a truck bomb detonated below the North Tower of the complex. The 1,336 lb (606 kg) urea nitratehydrogen gas enhanced device was intended to send the North Tower (Tower 1) crashing into the South Tower (Tower 2), bringing both towers down and killing tens of thousands of people. It failed to do so, but killed six people, including a pregnant woman, and injured over one thousand. About 50,000 people were evacuated from the buildings that day.The attack was planned by a group of terrorists including Ramzi Yousef, Mahmud Abouhalima, Mohammad Salameh, Nidal A. Ayyad, Abdul Rahman Yasin, and Ahmed Ajaj. They received $660 from Khalid Sheikh Mohammed, Yousef's uncle. In March 1994, four men were convicted of carrying out the bombing: Abouhalima, Ajaj, Ayyad, and Salameh. The charges included conspiracy, explosive destruction of property, and interstate transportation of explosives. In November 1997, two more were convicted: Ramzi Yousef, the organizer behind the bombings, and Eyad Ismoil, who drove the truck carrying the bomb.

Emad Salem, an FBI informant and a key witness in the trial of Ramzi Yousef, Abdul Hakim Murad, and Wali Khan Amin Shah, stated that the bomb itself was built under supervision from the FBI. During his time as an FBI informant, Salem recorded hours of telephone conversations with his FBI handlers, and reports submitted in court. In tapes made after the bombings, Salem alleged that an unnamed FBI supervisor declined to move forward on a plan that would have used a "phony powder" to fool the conspirators into believing that they were working with genuine explosives.

Ramzi Yousef (Urdu: رمزي احمد يوسف, romanized: Ramzī Yūsuf; born 20 May 1967 or 27 April 1968) is an Egyptian convicted terrorist who was one of the main perpetrators of the 1993 World Trade Center bombing and the bombing of Philippine Airlines Flight 434; he was also a co-conspirator in the Bojinka plot. In 1995, he was arrested by the Pakistani Inter-Services Intelligence (ISI) and U.S. Diplomatic Security Service at a guest house in Islamabad, Pakistan, while trying to set a bomb in a doll, then extradited to the United States.

He was tried in the U.S. District Court for the Southern District of New York along with two co-conspirators and was convicted of planning the Bojinka plot. He received two life sentences plus 240 years for his part in the 1993 World Trade Center bombing and Bojinka plot.

Yousef's maternal uncle is Khalid Sheikh Mohammed, with whom he allegedly planned the Bojinka plot. Mohammed is a senior al-Qaeda member accused of being the principal architect of the September 11 attacks in 2001. Yousef is serving his life sentences at ADX Florence, located near Florence, Colorado. He shares a cell block that is commonly referred to as "Bombers' Row" with Terry Nichols, Eric Rudolph, and Ted Kaczynski.