Before he went home to be reunited with his family, the respected journalist paid tribute to all of his supporters around the world.
"I would like to thank all the people who stood by my side and defended my position in every way. It gave me the power to stand firm and refuse to give up," he said.
There has been growing concern over Alluni's health in recent weeks and he admitted that his wellbeing had deteriorated during his imprisonment.
Alluni also revealed details of a smear campaign which began last year in Spain to discredit him, and said that was one of the reasons he went there.
"I came to Spain mainly to clear up those accusations. I didn't expect at all to be officially accused and imprisoned, which I consider was very humiliating and intimidating ... not only for me but for the millions of Aljazeera viewers."
He said he did not regret his decision to go to Spain and said he was happy to co-operate with any investigation. "I didn't sign any papers except for my temporary release on bail paper which says that my release came for reasons related with my physical conditions."
Alluni says he was the victim of a
smear campaign in Spain
The 56-year-old reporter came to the public's attention for his exclusive reports from Afghanistan during the US-led invasion of the country in October 2001.
Alluni has also interviewed Usama bin Ladin, and reported from the frontline during the invasion of Baghdad earlier this year.
He said on Thursday evening, he was deeply alarmed at the poor quality of translation from recent telephone conversations which did not take into account significant cultural aspects.
"I'm originally Syrian. For example, according to Syrian dialect when we say 'kaif al-shabab?' - 'how's the guys doing?' they translated it in a way that relates to a group said to be related to al-Qaida in Spain.
"It is really shameful and a lot of stuff was translated in this way."
''If I am found guilty, then I would be paying simply for doing my job"
When asked if he thought he would be found innocent at his trial, Alluni added: "If the Spanish authorities have any understanding of journalism and our culture, then yes. But if I am found guilty, then I would be paying simply for doing my job."
The reporter was arrested in September while on holiday in Granada, where he has a family home. He was taken to Madrid where he has been held in custody.
Spanish police arrested Alluni after accusing him of having links to members of al-Qaida's network, including Imad al-Din Barakat Yarkas, and Ilias Abu Dahdah, who was arrested on suspicion of being the ringleader of an Islamist cell that Spanish authorities dismantled in November 2001.
Alluni has denied any links to the cell which is suspected of having helped to prepare the September 11 attacks.
A Spanish judge ruled that the journalist should remain in custody pending further investigations into the purported links.
Judge Baltasar Garzon said he believed Alluni had helped to structure al-Qaida "at a national and international level by financing, controlling and coordinating ... this criminal organisation."
Freedom: Alluni talks to a
colleague as he is released
Garzon's conclusions, contained in a 25-page summary, showed he was convinced, after interviewing Alluni and after reading material from foreign intelligence sources, that there was sufficient reason to keep him in detention, pending charges.
Garzon has excluded any "direct relationship" between the reporter and "the most serious acts" of "terror" which al-Qaida is alleged to have carried out.
The arrest of the Aljazeera correspondent drew outrage from Aljazeera staff and journalism unions across the world.
The satellite station's journalists signed a petition of support for their colleague while anchormen and women appeared on screen wearing a badge carrying his picture.
Earlier today, a petition signed by Aljazeera staff demanding the release of their colleague was passed on to aides of the Spanish king, Juan Carlos, who was leaving Doha after a two-day visit.