By Steven Eke
BBC regional analyst
The story of Victor Yushchenko's rise to power is remarkable, given the context of the former Soviet Union.
Yushchenko will want a firm commitment from the EU on Ukrainian membership
With few exceptions, the region is home to undemocratic and authoritarian states.
Some of them, far from holding free and fair elections, have effectively set up family dynasties. Yet Ukraine's new leader came to power by electoral and legal process.
There will be much euphoria among Mr Yushchenko's supporters during his inauguration. But he will face many tasks and challenges, both internal and external, after taking office.
Mr Yushchenko will need to nominate a prime minister and form a cabinet.
The three leading candidates for the post are his close associate, Yulia Tymoshenko, the entrepreneur Petro Poroshenko and Oleksandr Zinchenko, the head of Mr Yushchenko's electoral movement.
The new president has been vague over who he wants to see in the job. And he has hinted at another candidate of a less political, technocratic orientation.
But there may be tensions, as Yulia Tymoshenko, in particular, has spent much of the time since the repeat election staking her moral right to the post.
Mr Yushchenko's government will need to be inclusive. That means including representatives from eastern Ukraine, as well as members of the Socialist Party.
Ukraine's current economic condition is generally seen as promising. There is a double-figure growth rate, and incomes are increasing.
But a recent report by the United Nations Development Programme concluded that Ukraine is in urgent need of systemic reforms. There are also severe social problems, particularly Aids and poverty.
Two of the most controversial issues Mr Yushchenko will need to address are privatisation and media reform.
He has already made clear that some of the most controversial privatisations of the last two years may be reviewed, in particular the country's largest steel mill, Krivorozhstal.
Mr Putin wants Ukraine to remain in its sphere of influence
On the media, Mr Yushchenko is known to favour some sort of public service broadcasting, a big ambition for a country without any tradition of one.
A divisive issue will be the possible opening of a number of high-profile criminal cases. They may include that of the murdered journalist, Heorhiy Gongadze, as well as those implicated in electoral fraud or calling for regional sovereignty during the election campaign.
Crucially, Mr Yushchenko has said he will name those he alleges were responsible for poisoning him.
Externally, the challenges are also great. Mr Yushchenko is heading to Moscow shortly after his inauguration.
There are issues over which Russia and Ukraine are unlikely to fully agree.
One of them is whether Ukraine, a major regional economic player, will join what Russia calls the "common economic space".
President Vladimir Putin indicated how important he views this when he included it in his congratulatory message to Mr Yushchenko, who has promised to align his nation with Europe and the West.
Mr Yushchenko may also bring a new urgency to Ukraine's efforts to build a closer relationship with the EU.
The man widely tipped as Ukraine's next foreign minister, Boris Tarasyuk, says Ukraine sends signals to the EU, only to get none back in return.
Ukraine is likely to push hard for some sort of statement from the EU. Its new leadership may ask why countries with similar problems, such as Bulgaria and Romania, have been offered firm guarantees until now denied Kiev.