Ivan Yordanov Kostov was born in Sofia on 23 December 1949.
1974 - completed his university studies at the Karl Marx Higher Institute of Economics, Sofia.
Later, in 1974, he joined the lecturing staff of the same academic institution as Assistant Professor.
1979 - Senior Assistant Professor at the Scientific Communism Department of the "V. I lyich Lenin" Higher Institute of Mechanical and Electrical Engineering, Sofia (now Technical University).
1982 - received a second university degree in Mathematical Modelling of Economic Processes from the Kliment Ohridski University in Sofia.
1990 - elected deputy from the UDF to the 7th Grand National Assembly and Chairman of the Economic Affairs Committee. Finance Minister in the UDF-BSP coalition government headed by Dimitar Popov.
1991 - UDF deputy to the 36th National Assembly. Associate Professor at the Technical University in Sofia.
Minister of Finance in the UDF cabinet headed by Philip Dimitrov until the end of 1992.
1993 - Deputy Floor Leader of UDF's parliamentary group.
Leader of the UDF; deputy to the 37th National Assembly.
Following the April 1997 elections, as deputy to the 38th National Assembly, he was appointed Prime Minister.

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In December 1999, under increasing pressure on the part of  the public and the parties represented in parliament, demanding the resignations of corrupt functionaries or such with a low approval rating, he made some replacements and restructuring in the UdDF cabinet, forming practically a new one, a second UDF cabinet, for only Finance Minister Radev, Ecology Minister Maneva, Minister of Culture Moskova and Labour Minister Neikov of the old cabinet kept their posts. The structural changes were made with a view to the EU membership invitation and the cabinet was joined by some figures that were entirely unknown to the public.
In the formation of the new government, Kostov removed without any explanations Minister of the Interior  Bogomil Bonev, although Bonev's rating of approval was very high. Then Kostov could not but follow the course of the scandalous disclosures made by Bonev. Bonev told about the unlawful privatization of the water power stations and Kostov stopped the procedure. Bonev revealed the compensatory bonds fraud, and on 9 June 2000 Kostov dismissed  Bozhkov as Bulgaria's chief  negotiator with the EU.
On 12 June 2000 Bonev publicized new scandalous information in connection  with the privatization of Bulbank and if proved, Kostov would have to hand in his resignation, demanded already by Bonev.  The reaction of the opposition was not late too. Dogan commented that Kostov was "scared and inadequate", and also that "for the past three years Bulgaria has been plundered like no one else before did". He demanded the resignation of Foreign Minister Mikhailova and Finance Minister Radev.

In fact Kostov's  field for manoeuvring is quite narrow. It is least likely for him to resort to a large-scale purging of the corrupt in the UDF and the government, because this will only lead to the break-up of the UDF, but also because he himself is the originator of the now functioning system and is directly responsible for it. If Bozhkov follows in the steps of Bonev with scandalous disclosures, then Kostov will surely have to resign. It is more likely for Kostov to begin purging the lower tiers of second-echelon functionaries of the UDF and the public administration. The resignation of Mrs. Zhanina Kalinkova, deputy regional governor of Dobrich and the started removal of customs officers, are signs along this line of development. Inside the UDF, the pressure on Kostov will inevitably grow from two sides - by corrupt functionaries and by decent party members alike. The result may be a chain reaction of resignations within the UDF and the government.
A favourable circumstance for Kostov is that so far none of the opposition political forces has demanded early elections and has offered a serious governing alternative. Nevertheless, it is quite likely for Kostov to form i n the autumn a new cabinet to face the 2000 parliamentary elections. It is important for him to keep the UDF intact  until these elections. Kostov's position will depend largely on the future disclosures of corruption made not only by Bonev, but also by other removed functionaries. At present, Kostov has no winning move. The ideas of a new cabinet, to be headed by Zhotev or Mikhailova,  recently launched  in the media are not serious. It seems a more realistic development for Kostov to  try to form a coalition government with the MRF or the EuroLeft in the autumn. In any case, both the UDF and Kostov himself have lost much of their glory and that is why their ratings after the local elections have preserved a downward trend.

After UDF's failure in the June 2001 election, Kostov retired from the leading positions, but his influence on Ekaterina Mikhailova, who then became the party's leader, and on the other leading figures too, persisted.

2001 - Deputy to the 39th National Assembly.
2004 -  Some time after Nadezhda Mikhailova is elected leader of the UDF, Kostov heads a groups of MPs who split from the UDF (Union of Democratic Forces) to form a new parliamentary group of the United Democratic Forces and, later, found a new political party - Democrats for a Strong Bulgaria which is due to take part in the 2005 parliamentary election.
2005 - in the June 25 parliamentary elections wins a seat in the 40th National Assembly from one of Sofia's three constituencies.
2006 - Kostov's DSB nominee for president, Nedelcho Beronov, fails to get the voters' support.
2009 - elected MP in the 41st National Assembly with the Blue Coalition (UDF and DSB) ballot list.

Working knowledge of English and Russian. Married, with two daughters. Eastern Orthodox Christian.