Brazilian pollster Quaest released voting intention surveys on Tuesday, August 25, for the governor races in the states of Mato Grosso do Sul and Rondônia, with results broken down by gender, age, education, income, race, religion and political self-identification. Both surveys interviewed 804 people aged 16 or older in each state between August 21 and 24, with a margin of error of 3 percentage points and a 95% confidence level, according to G1.
In Rondônia, a state in Brazil's northern Amazon region, Marcos Rogério of the Liberal Party (PL) leads with 24%, followed by Adailton Furia of the Social Democratic Party (PSD) with 21%, a statistical tie given the margin of error. Expedito Netto of the Workers' Party (PT) and Hildon Chaves of União Brasil each poll at 10%, while Samuel Costa of the Brazilian Socialist Party (PSB) has 2% and Pedro Abib of the Brazilian Democratic Movement (MDB) has 1%. The poll is registered with Brazil's top electoral court, the TSE, under numbers RO-05711/2026 and BR-00490/2026. Among men, Rogério's lead widens to 31% against Furia's 22%; among women, the two are tied at 19%. Furia has an edge among voters with a college degree (26% to 23%) and among Black voters (21% to 18%), while Netto performs best among voters 60 and older, where he reaches 18%.
In Mato Grosso do Sul, a farming state on the border with Paraguay and Bolivia, incumbent Governor Eduardo Riedel of the Progressive Party (PP), who is seeking reelection, leads comfortably with 40% of first-round voting intentions, according to the poll commissioned by broadcaster TV Morena. He is followed by Fábio Trad of the PT with 13% and Delcídio Amaral of the Brazilian Renewal Democratic Party (PRD) with 8%. Rounding out the field are João Henrique Catan of Novo with 3%, Lucien Rezende of the Socialism and Liberty Party (Psol) with 2%, and Daniel Lemes of PCO, economist Renato Gomes of DC and Jeferson Bezerra of Agir, each with 1%. That poll is registered with the TSE under numbers MS-00793/2026 and BR-04312/2026.
Ahead in nearly every bracket
Riedel leads in almost every demographic segment measured by Quaest in Mato Grosso do Sul. His advantage grows among voters with a college education, where he polls at 55% against Trad's 15%. Among voters aged 35 to 59, he reaches 46%, his strongest age bracket. Trad performs best among voters 60 and older, where he climbs to 20%. Riedel's government has a 62% approval rating and 16% disapproval, according to the same Quaest survey, while in Rondônia, Governor Marcos Rocha of the PSD has 46% approval and 34% disapproval.
The polling round also covered other races in both states. In Mato Grosso do Sul, Quaest's unprompted Senate poll showed Nelson Azambuja at 22%, Marcos Contar at 15%, Soraya Thronicke at 11% and Vander Loubet at 9%, though 86% of voters remain undecided in that format. In the presidential race within the state, Flávio Bolsonaro of the PL polls at 33% and Lula of the PT at 27%. In Rondônia, the presidential race shows Flávio at 45% and Lula at 25%, according to the same Quaest round.
Voters in both states head to the polls for the first round in October. If no candidate wins an absolute majority of valid votes, a runoff will be held between the top two finishers in each state.