Merhaba
In june I'll be in Istanbul for a month.
I'm looking for an accomodation.
I'd like to stay in an university dormitory, it is possible?
Can you suggest something to me?

Thanks

Take a look at this page http://www.istanbul.edu.tr/english/a_health.php and maybe you can send them an email?

I tried to reach Istanbul üniversitesi, and asked them whether it was possible to stay at their campus while I'd be there, but they never replied..

If you want to find a place in student's hostel, you will have to find it in private hostels, because I don't think so called "devlet" hostels would help. As far as I know, Istanbul Universitesi doesn't have its own hostels - but you can try to reach an organization KYK (Kredi ve Yurtlar Kurumu), which is the administration of all national students' hostel in whole Turkey.

thanks for your useful suggestions!