For a jubilant Iran, it is proof positive that a hostile United States and bellicose Israel have failed to isolate or intimidate the Islamic republic over its nuclear programme.
Iran says 36 heads of state and government will be in Tehran tomorrow for the two-day summit of the 120-member Non-Aligned Movement (Nam), which opens with an address by Iran's supreme leader, Ayatollah Ali Khamenei.
Other countries will be represented by princes, foreign ministers and ambassadors.
The summit is "a slap in the face for Israel" and a "powerful blow" to the US and its allies, Iran's hardline Kayhan newspaper trumpeted.
As Egypt yesterday formally handed over the three-year rotating Nam leadership to Iran, Tehran vowed it would "never stop" its uranium enrichment programme.
Among Iran's most prized guests are the Egyptian president, Mohammed Morsi, and the Indian prime minister, Manmohan Singh, whose country remains a significant importer of Iranian oil.
Iran hopes to conclude numerous economic deals with countries attending the summit.
Ban Ki-moon, the UN secretary general, will attend in an observer role, defying public pressure from the US and Israel to stay away.
His spokesman said he would use the opportunity to convey "clear concerns" about Iran's nuclear programme, human rights and support for the Syrian regime.
Iran has promised to unveil a "comprehensive package" to resolve the Syrian crisis on the side-lines of the Nam conference.
But few hold out much hope of an Iranian-sponsored breakthrough, given Tehran's repeated assertions that the Syrian president, Bashar Al Assad, is battling a western-inspired uprising aimed at toppling his regime to weaken Iran.
Iran is using the summit to make a "visually forceful case that attempts by the US to isolate it have failed", said Farideh Farhi, an Iranian scholar at the University of Hawaii. "And [that] the touting of Iran and its nuclear programme as a global problem is a function of US hostility and pressures, and not reflective of the true sentiments of the international community."
But what Iran hopes will be a public-relations bonanza could yet turn sour over its staunch support for the Syrian regime, its main Arab ally for three decades.
Mr Morsi yesterday urged Mr Al Assad's allies - among them Iran, Russia and China - to help remove him from power. "Now is the time… for this regime that kills its people to disappear from the scene," he told Reuters.
As host, Iran will prepare the first draft of the summit's final document, likely to include statements affirming its right to peaceful nuclear technology, condemnation of Israeli threats against it, and censure of Israel's occupation of Palestinian lands.
Iran is seeking to re-build Nam as a counterweight to dominance by the five, veto-wielding permanent members of the UN Security Council, in particular the "global arrogance", America.
"We share the concerns of many [Nam] members that the UN Security Council has increasing power in the face of the [UN] General Assembly," Iran's foreign minister, Ali Akbar Salehi, said on Sunday.
Nam members, mostly from Asia, Africa, the Middle East and Latin America, form the biggest single voting bloc in the 193-member General Assembly.
To Iran's evident satisfaction, US opposition to its hosting the summit has given the movement, often dismissed in the West as an anachronistic talking shop of disgruntled developing nations, more publicity than it has enjoyed in years.
One of Iran's key aims for the "greatest political summit" in its history is to win international backing for its nuclear programme and a show of solidarity against western sanctions.
Iran denies western suspicions it is seeking the ability for a nuclear weapons "break-out" capability, insisting its atomic programme is solely peaceful in nature.
Tehran has been decorated with coloured lights and banners, one of which reads "nuclear energy for all". Another, less punchy, proclaims: "The Non-Aligned Movement represents the struggle against racism, colonialism, hegemony and foreign oppression."
But a bid to show transparency over its nuclear work seemed to backfire yesterday when a foreign ministry spokesman said there were no plans to show its nuclear sites to diplomats during the summit - despite an earlier offer by a deputy foreign minister.
Mohammad Mehdi Akhoundzadeh hinted on Monday that Nam diplomats might be allowed to tour the Parchin military base, which the UN nuclear watchdog says may have been used for nuclear-related explosives trials.
But the foreign ministry spokesman, Ramin Mehmanparast, later appeared to dismiss the idea.
"We have no specific plans for a visit to Iran's nuclear installations by foreign guests participating in the summit of Nam member countries," he was quoted as saying by the state news agency, IRNA.