She spent six weeks in jail in 2000 while being investigated for her business activities. Her husband and father-in-law were also imprisoned. Tymoshenko says the arrests were all politically motivated and ordered by former President Leonid Kuchma, whom she implacably opposed.
Now, one of her government's declared priorities is to battle corruption. Toward that end, many inside and outside the government would like to see an investigation launched into allegations that Kuchma was guilty of fraud and corruption while he was president. Kuchma has also been questioned in connection with the slaying of an investigative journalist five years ago.
Tymoshenko sat down with RFE/RL this week in her wood-paneled office in the cabinet building in Kyiv. Dressed in a pink jacket and black dress, with her blond hair wound around her head in her trademark braid, Tymoshenko appeared calm and at ease, but made no secret of her strong desire to see Kuchma answer for his alleged crimes.
"I'm not a prosecutor or a judge. I can't deliver verdicts, and I can't initiate criminal proceedings," Tymoshenko said. "But as a person who has been a politician, I know that nobody exists who has committed bigger crimes against Ukraine -- [against] its interests and against the Ukrainian people -- and that if [Kuchma] is not made to answer before the law for what he has done to Ukraine and to our people, then I think there will be little justice in this life."
She says the desire to see Kuchma stand trial is not motivated by revenge. Rather, she says, such a trial would demonstrate to state officials that the new regime does not tolerate corruption -- a problem she likens to "a cancer that penetrates every cell of our society."
"Corruption -- the shadow economy -- is a legacy that has been left to us by officials with links to [oligarchic] clans which we have not yet been able to change because the sacking or appointment of officials is done according to specific procedures. In instances where we could dismiss them by decree, we did. But officials who were appointed by parliament or who have been in their positions for many years are still there, and those links [between oligarchic clans and officials] are still blossoming. But I think that step by step, we will change this and put honest people in these posts."
Some 18,000 officials have already been dismissed across Ukraine, but Tymoshenko says not all of their replacements have been ideal. She says new procedures will be introduced to ensure that new state employees are honest.
During the two days RFE/RL spent with Tymoshenko, she met with the French ambassador and apologized repeatedly as she paused to variously answer each of her five office telephones, including a call from Yushchenko himself.
Outlining what she wants to achieve before parliamentary elections scheduled for spring 2006, she said: "Our priority is to build a fair system in Ukraine. That means in the legal system, in economic activity, in the social welfare system, so that people can feel that the government is treating them fairly. That means that we have to provide a dignified, reasonable standard of living for people. All our priorities revolve around this."
One of the most important factors in building a fairer society, she emphasized, was pushing through a sweeping reform of Ukraine's judicial system -- a system she said "has become rotten and which operates only on the basis of corrupt judges -- not on a proper system, not on responsibility."
Tymoshenko knows her government will not be considered successful until it brings about significant improvements to the economy. She says she wants to create conditions that will make the country's business sector confident about operating transparently and help it extract itself from Ukraine's vast shadow economy.
She believes businesses will be willing to pay taxes if they are treated fairly.
"Without a doubt, we have to deal with the shadow economy, which doesn't allow the average person to live properly, to adequately finance their health costs and education. Everything that is needed for the budget -- that which should go to the state and to those people who have only small resources -- remains in the shadows," she said.
"I very much want people who are socially deprived or who are unable to work to be protected -- children, invalids, the elderly," she added. "This can be done on the basis of providing the conditions needed for honest businesses to develop in every sphere of our lives and to have a basis for economic growth. We -- the president and the government -- will work to the utmost to encourage as many investment projects in Ukraine as possible so that we can feel that we are economically strong."
Tymoshenko's government has been harshly criticized because of a sharp hike last month in the value of Ukraine's national currency, the hryvna, against the dollar. Many Ukrainians keep their savings in dollars and saw the value of their nest eggs decline sharply.
Tymoshenko says Ukraine's National Bank works independently of the government and took the revaluation decision on its own. She denies reports that she encouraged the move, but notes that most Ukrainians are paid in and buy things using the national currency. She believes a strong hryvna will benefit the poorer members of society by increasing their purchasing power.
Tymoshenko has also been plagued by poor relations with Russia. The Kremlin is suspicious of her and believes her to be anti-Russian, which she denies. Before she became prime minister, Moscow had issued a warrant for her arrest. It accuses her of bribing army generals during a corrupt business deal in the past. Tymoshenko canceled an official visit to Moscow in April after Russia's prosecutor-general said the warrant was still valid.
She says Russia must change the way it views Ukraine. "I think what is needed to build a partnership and civilized relations is for Ukraine and Russia to both understand that the relationship -- the partnership between Ukraine and Russia -- should be on an equal basis," she said. "But it seems to me that Ukraine sees these civilized relations in one context, and Russia sees them in another. Russia became used to Ukraine being insignificant or seeing it as an insignificant country that acted in accordance with the interests of the Russian Federation."
She added: "I think that if we are to see in each other the possibility of friendship in this geographical and political horizon, then we have to acknowledge that we are sovereign nations, equal nations, and that we want good things for both our peoples. And therefore we have to find a compromise and not to apply pressure or to use -- shall we say -- unusual methods."
Tymoshenko says she's proud of her close working relationship with Yushchenko, which she says is built on mutual trust, respect, and a shared moral outlook. She opposes constitutional changes due to be introduced that would devolve many of the president's extensive powers to the prime minister.
She says Yushchenko's supporters were forced to vote for the changes last winter as part of a compromise deal with pro-Kuchma authorities during efforts to end the country's political crisis. In theory, the changes will make her position more powerful. Nevertheless, she says she has challenged them in Ukraine's Constitutional Court and hopes they will not be implemented.
Tymoshenko has pledged that her government will run next year's parliamentary elections honestly and will do everything to minimize electoral abuse. However, she thinks there may be attempts to cheat in some of the areas in eastern Ukraine known as being strongholds of the old government.
But she says she's certain the old regime will not be returned to power.
"They won't return. I don't think there will be a resurgence, and I'm sure that our united team, with Viktor Andreyevych [Yushchenko], will only be strengthened by those political forces which will join us and will create a common political platform -- and these are key figures in our society," she said. "I don't see our team being split apart. I don't know what the exact configuration will be. The important thing is that the configuration will be within one team. Our aim will be to get the largest number of seats in the parliamentary elections."
A number of events are scheduled on Sunday and Monday to mark Tymoshenko's first 100 days in office. They include a public walkabout in an open-air museum near Kyiv and on the capital's main street, where she is due to field questions about her record directly from the public.