Immediately after his release, Diokno set up the Free Legal Assistance Group or FLAG in 1974, which gave free legal services to the victims of martial law. It was the first and largest association of human rights attorneys ever assembled in the nation. In court, Diokno personally defended tribal groups, peasants, social workers threatened by exploitation, and military atrocities, which he represented pro-bono. FLAG popularized developmental legal aid and even doled out allowances to its clients. This has led to new laws requiring newly sworn-in lawyers to provide free legal assistance for a certain amount of time. FLAG handled 90 percent of human rights cases in the country as well as built programs to educate citizens about human rights. Diokno was also involved in documenting cases of torture, summary execution, and disappearances under the Marcos regime.