The contest for two Senate seats in Mato Grosso is shaping up to be one of Brazil’s most closely watched races in 2026. A diverse field of politicians — from established incumbents and state leaders to bolsonarist figures and former governors — have signalled their intentions, setting up a competitive campaign that will test party structures and regional loyalties.
Mato Grosso Senate race overview
Janaina Riva, a state deputy for the MDB, is currently the most visible pre-candidate. Backed by the state party leadership, she has been actively campaigning since early 2025 and consistently places near the top in local polls, typically behind Governor Mauro Mendes of União Brasil. Mendes has not yet confirmed his candidacy and has said he will only decide in April 2026, the legal deadline for governors to resign if they intend to run for the Senate. Close allies expect him to enter the race, and his popularity has placed him in a leading position throughout the polling period.
Minister Carlos Fávaro of the PSD has announced his intention to seek re-election. As a minister favoured by the federal administration, Fávaro is likely to benefit from strong support from the Planalto. Polls show him fluctuating between third and fourth place, but his national profile and government backing make him a formidable contender.
Senator Jayme Campos of União Brasil is exploring a run for governor. He maintains that, should a gubernatorial bid not materialise, his re-election to the Senate would be a natural outcome. Campos still faces internal party questions that must be resolved before he can finalise his plans.
The bolsonarist wing has rallied behind federal deputy José Medeiros of the PL. Medeiros has the party endorsement and the public approval of former president Jair Bolsonaro. He typically appears in the mid-pack of polls. His candidacy may attract the conservative base in a state known for significant bolsonarist support.
Other contenders include former governor Pedro Taques of the PSB, who seeks a return to the Senate after previously serving and resigning to take up the state governorship. Taques draws on national recognition and currently polls in the lower tier. Antônio Galvan of the Democracia Cristã, an ultraconservative figure aligned with bolsonarist positions though without direct Bolsonaro backing, is again on the ballot and is building party structure for the contest.
Margareth Buzetti of the Progressistas has also signalled a senate bid following a break with Carlos Fávaro. As second alternate senator she served in the Chamber for three years and is known for legislative work on tougher measures against femicide. Her polling numbers remain low for now, but she brings a distinct profile to the race.
The calendar will be decisive. With governors required to resign by April 2026 if they intend to run, the next few months will reveal key alliances and strategic withdrawals. Party cohesion, endorsements from national leaders and voter response to state governance will shape which candidates consolidate support.
For Mato Grosso, the 2026 Senate election is not only about individual names but also about how national and local forces interact. The contest will test the strength of federal backing, regional party machines and the resonance of ideological appeals across urban and rural constituencies.
Key Takeaways:
- The 2026 Mato Grosso Senate race has opened with several established figures and newcomers vying for two seats.
- Janaina Riva leads mobilisation efforts while Governor Mauro Mendes remains a likely contender if he resigns to run.
- Carlos Fávaro is positioned as a Planalto‑backed candidate, with bolsonarist and centre figures also in the field.
- The Mato Grosso Senate race will be shaped by alliances, party decisions and the governor’s April 2026 resignation deadline.
