Cameron tweeted his pleasure just hours after Qatada, 53, left Britain aboard a private flight bound for Jordan from RAF Northolt in west London.
"Dangerous" Qatada was deported after a decade-long legal battle which, according to a report, cost Britain at least 1.7 million pounds.
Shortly after the plane carrying Qatada, once considered the right-hand man of Osama Bin Laden in Europe, left the UK, Home Secretary Theresa May said: "I am glad that this government's determination to see him on a plane has been vindicated and that we have at last achieved what previous governments, Parliament and the British public have long called for."
Following numerous courtroom battles, it was a treaty signed between the UK and Jordan that finally secured Qatada's departure, giving the radical preacher the assurances he needed to leave his taxpayer-funded home behind.
The agreement, announced by the home secretary, earlier this year, aimed to allay fears that evidence extracted through torture will be used against the father of five at a retrial.
Keith Vaz, the chairman of the home affairs select committee, said: "Only 446 days after the home secretary said Abu Qatada would be on a plane shortly, he has finally reached the end of the runway. In the end, it was the king of Jordan who secured his departure by agreeing to this treaty."
"The home secretary's legal advisers will have questions to answer as to why they didn't conceive of this scheme earlier which would have prevented a cost to the taxpayer of 1.7 million pounds."
