Jader Fontenelle Barbalho (born 27 October 1944) is a Brazilian politician, businessman and landowner from the state of Pará.

Starting a political career in Belém with humble possessions, Barbalho became a millionaire after decades in public office.

In 2000, Barbalho was the President of the PMDB party and Senator when a wave of corruption allegations against him took national headlines, involving embezzlement of public funds at the Superintendência de Desenvolvimento da Amazônia (SUDAM - Superintendence for Amazon's Development) development agency and the Instituto Nacional de Colonização e Reforma Agrária (INCRA - National Institute for Colonization and Agrarian Reform).

He is alleged to have used his power base in the Amazonian state of Para to influence which projects were approved by SUDAM.

[2] On 22 February 2002, Senator Antônio Carlos Magalhães gave an interview to state prosecutors in which he hinted at corruption involving Cardoso, Barbalho, the PMDB, the PFL, and the Supreme Court.

The interview, which was leaked to the press, prompted Cardoso to begin sacking government appointments linked to Magalhães, most notably cabinet ministers Rodolpho Tourinho (mines and energy) and Waldeck Ornelas (social security) on 23 February.

In 2002, with public opinion favouring investigation into allegations of government corruption, the opposition sought the votes of 27 Senators and 171 Federal Deputies in Congress necessary to constitute a joint working committee (CPI) against Barbalho.

Afterward, political maneuverings persuaded enough legislators to change their minds, and the CPI threat was ended.

On 16 May Saturnino Braga, the rapporteur of the Senate Ethics Committee, concluded that Magalhães and the government leader in the Senate, José Roberto Arruda of the Federal District, were guilty of having violated secrecy rules in the June 2000 vote that expelled Federal District Sen. Luis Estevão from Congress.

With Arruda and Magalhães out of office, Congress, at risk of becoming ineffectual, continued to be mired in scandal as more allegations of past corruption involving Barbalho surfaced.

In the face of mounting evidence and the likelihood of impeachment, he resigned from the Senate on 4 October, following the same path of Magalhães and Arruda.