"I have medical, scientific, human, romantic and political reasons to continue to lead the government and pursue the candidacy with more strength than before," Chavez told Correo del Orinoco newspaper.
"Not for a moment did I think of leaving the presidency," he continued, adding that he would have left his post if he had valid health reasons to do so.
Chavez returned to Venezuela late Saturday after undergoing chemotherapy treatment in Cuba, declaring himself free of "malignant cells" and ready to resume his full work schedule.
"I returned in better condition than I was in when I left," Chavez declared as he stepped off the plane.
The 56-year-old leader underwent an operation in Cuba a month ago for a cancerous tumor in his pelvic area.
After being welcomed at the airport by members of his cabinet and top military officials late Saturday, Chavez expressed confidence for a quick recovery.
"I underwent examinations and I must tell you that doctors did not find any malignant cells in any part of my body," the president told local television.
He cautioned, however, that there was a risk of relapse and predicted new medical procedures he did not identify.
"We will conquer this disease with the help of God and medical science in order to continue paving the way for a new motherland," he promised.