IS there any Eastern Europe country who is not first world.And if yes who?

sorry i didnt spell what i ment...the question was if there is any eastern europe country that has become a first world country
I know some countries are now belong to EU but i m not sure if there is any that is economical developed yet

Republic of Ireland

The terms first world, second world, etc. have been outdated for at least 16 years, so your question doesn't make much sense. But in case you were wondering about general westernization, then yes, there are Eastern European countries that belong to NATO and/or the EU.

Slovenia is an Eastern European country that is developed. Hungary and Chech Republic are also doing quite well. Also Croatia is heading that way with theit tourist offer becoming ever so popular and in the top 5 of the summer destination lists (however Croatia still has plenty of issues to deal with).

Kosovo is on the way.
Serbia, on the other way.

Slovenia is in the EU and NATO and it's among other devenloped countries (like USA,UK, Italy,...). :)

Greece