Chavez said he would go to Havana on Saturday "to begin what we've called the second phase."
Chavez said he was sending a letter to the president of Venezuela's National Assembly to secure authorization for his trip, as required by the constitution.
The 56-year-old announced his plans after meeting with Peruvian President-elect Ollanta Humala at the presidential palace. Humala wished Chavez the best in "this personal battle you are leading."
Chavez underwent surgery in Cuba on June 20 to remove a cancerous tumor from his pelvic region. He has said the tumor was the size of a baseball.
Chavez had aknowledged on Wednesday for the first time that he expected to eventually undergo chemotherapy or radiation treatment.
His revelation of his trip to Cuba came after reports from Brazil that the Venezuelan leader planned to undergo his next round of treatment at Sirio-Libanes hospital in Sao Paulo, which is considered one of the best hospitals in South America.