The PDP said the ruling by the tribunal was, "an alarming miscarriage of justice".
The Peoples Democratic Party has said it has proof that the 2019 Kogi State governorship election was rigged by Yahaya Bello of the All Progressives Congress.
Kola Ologbodiyan, spokesperson for the PDP, in a statement on Sunday said it would appeal the decision of the Election Petition Tribunal which affirmed Bello as winner of the election.
The PDP said the ruling by the tribunal was, "an alarming miscarriage of justice".
The statement reads in part, "Our party was able to lay incontestable evidence of over-voting, massive thumb printing, voter intimidation, thuggery, violence and other malpractices used by the APC and compromised Independent National Electoral Commission officials to rob our candidate and the people of Kogi State of their mandate.
"The PDP expressed shock that despite the overwhelming evidence before the tribunal, proving that Governor Yahaya Bello did not win the election, justice was thwarted to the disappointment of the people of Kogi State and generality of Nigerians.
"In fact, the lull and despondency that have enveloped Kogi State since the tribunal's flawed verdict is an indication that the judgment failed to uphold justice in the genuine aspiration of the people of Kogi State in the election.
"The fact remains that the evidences are clear that our candidate is the genuine choice of the people and our party is confident that the Court of Appeal will uphold justice in this matter.
"The people of Kogi State now look up to the Appeal Court to reverse this injustice endorsed by the tribunal, given the evidence laid, as affirmed by the courageous verdict of Justice Ohimai.
"The PDP commends Justice Ohimai for his fearlessness in upholding the truth and showing that there is hope in the institution of the judiciary, which our party is confident, will be further established by the Appeal Court in this matter.
"Our party is confident that the Appeal Court will address the substance of the case, which the tribunal overlooked in rendering its defective judgment.
"The people of Kogi State deserve a government elected by them and not one imposed by enemies of democracy and compromised officials at INEC."