Before leaving for Bolivia, Che could meet his wife and his children (except Hildita) for the last time. He was in disguise and the children were told that he was a friend of Che. Once Aliusha hurt her head and Che, trying hard not to behave as a father, consoled her. She later whispered to her mother that she thought the old man was in love with her.
In November Che arrived at La Paz (Bolivia) via East Germany and Prague. His passport was for the name Adolfo Mena-González and he was carrying a letter from the Organization of American States stating that he had been commissioned to write a report on social and economic conditions in the Bolivian countryside.
He stayed in the Hotel Copacabana where he took some photos of himself - these were found by the Bolivian military and resurfaced only in 1991.
Bolivia was another Latin-American country, exploited and oppressed by the USA, with a puppet president (René Barrientos) on the top while its people was starving and 42% of the population died of mal-nutrition. The country has frontiers with Chile, Argentina, Peru, Paraguay and Brazil so the revolution could have been exported to these countries easily.

On 5th November Che - using the name Ramón - arrived at a farm in Ñacahuasú, which  was the site of the Bolivian camp. He started to write a diary about his experiences (this became the Bolivian Diary).
The first days were spent on inspecting the area nearby while mosquitos were biting their skin. Then they dug a tunnel to hide all those things that could compromise them while new men and arms were arriving. 
By the end of December all the Cuban combatants arrived at the camp, two caves were dug in the rock (one for the radio station, one for hiding weapons and food) and they could bake bread.   
On 31st December Mario Monje-Molina, the secretary general of the Communist Party of Bolivia arrived at the camp. He wanted to take the political and military leadership of the guerrilla as long as they were in Bolivia, but Che refused it. He remembered the lesson of the Congo campaign and he also knew that Monje-Molina had no guerrilla warfare experience. So Monje-Molina left and the communist party withdrew its support from Che.

In January Loyola Guzmán-Lara arrived. She was a member of the Bolivian Communist Youth, but later she was expelled because of her supporting the guerilla. She started to work for Che who was very impressed with the brave woman.
In February Che organised a march to explore the area and give his new recruits a taste of the guerrilla life - during that he lost two men. (They drowned in the river and no one could save them.)

In March he lost his best Bolivian fighter and some of the recruits deserted. On 20th March the group returned to the camp. Soon the Bolivian army discovered one of the guerrilla camps, a man and a mule were captured.
The operators decoded messages from La Paz while the men hunted for food, laid ambushes for the army and quarrelled with each other. There were some discipline problems, even a rivalry between Cubans and Bolivians that Che found intolerable.
On 23rd March the first guerrilla action took place. A Bolivian army column fell into an ambush: 7 soldiers were killed, 4 wounded and 14 were taken prisoner. Weapons were captured and army plans were given away.
As the army knew about the camp, Che divided his men into three groups (rearguard, vanguard and main column - this last one was led by Che) and they started a new march.

Besides the physical training, Che always found time to read. He carried a bunch of books in his rucksack - books about history, literature, culture and medicine - and even a notebook, full of his favourite poems that he had copied out.
Che wrote 'Message to the Tricontinental Conference of Solidarity with the Peoples of Asia, Africa and Latin America' which was published in Havana on 16th April. He called for the creation of 'two, three, many Vietnams' to dilute US forces in Vietnam by forcing the Americans to fight on more than one front. The closing words became especially famous:
"Our very action is a battle cry against imperialism, and a battle hymn for the people's unity against the great enemy of mankind: the United States of America. Wherever death may surprise us, let it be welcome, provided that this, our battle cry, reaches a receptive ear, that another hand picks up our weapons, and that other men are ready to intone our funeral dirge with the staccato sound of machine guns and new battle cries of war and victory."

By the end of April Che lost two Cuban fighters - one of them was one of his best guerrillas. There were no new recruits and they lost contact with the rearguard group. Their walkie-talkies (Che called them radio transmitters) were useless as they were out of range.
One of Che's men, Ciro Bustos and the French journalist, Régis Debray left the column and next day they were captured by the Bolivian army, then taken to prison for thirty years. (In the end, they had to serve only three years.)
Che heard on the radio that US Green Berets and helicopters were arriving at Bolivia (to catch the guerrillas) but he did not care about it.

In May they had hardly any food and they were not sure about their geographical position. They also were unable to make contact with the rearguard or Cuba. Che's column consisted of twenty-five men only - and there were no new recruits. As a precaution, Che changed his name from Ramón to Fernando.
Meanwhile the Bolivian army started a new tactic: they arrested everyone who had collaborated with the guerrillas.
On 19th and 20th June Che was busy with extracting the sick teeth of his fellow-guerrillas and he was given the nickname, Fernando the Tooth-Puller.
In July the guerrillas gained more combat experience by participating in skirmishes and their morale was high - even though they still had no contact with the population.

From 31st July to 10th August the Organisation of Latin American Solidarity held a conference in Havana and Che was made its Honorary Chairman in absentia.
On 4th August a deserter led the Bolivian army to the guerrillas' main arms cache in the camp. Arms, documents and medicine were lost - it was a huge blow. Furthermore, the main column still had no contact with the two other groups, with Cuba or with the outside world. The guerrillas were demoralised and starving, and some of them were even ill.

In September the radio said that one guerrilla unit had been wiped out - possibly the rearguard, then on 15th Loyola Guzmán-Lara was detained, her house was searched and some photos of her in the Ñacahuasú camp were found.
By 26th September the guerrillas were incircled by government forces. Three guerrillas were killed, one disappeared.

October began without incident. They kept on marching towards La Higuera. His last entry in his diary was written on 7th October 1967.