I was out of status for a semester because we forgot to renew my i 20. However I was continuing the classes. Then I re-entered to US with new i20 and sevis (No issues) and came back to status in 2009. Now I am filing my 485. I am confused whether I have to mention it or not. My lawyer is saying , since I entered US with new i 20, I dont have to mention.
Please suggest whether my lawyer is correct or I have to mention.

Thanks in advance.

what is your current status, what was your status and how long did you remain out of status all matter to file i485. however, if your illegal stay is no more that 180 days i wouldnt worry about it. if its more that 180 days its better to let officials know. and since you've a legal status right now you have nothing to lose.

Thanks Khaikhok.

My i 20 expired on 6/30/08.
New i 20 issued on 11/18/2008 but was admitted on Jan 2009 after re entering to USA.
Which date should we consider? Issued date or re entering date?
If we count issue date then its less than 180 days and if we count re entering date then it exceeded the 180 days.

If you entered US with valid I20 2nd time. Your previous status does not matter, you don't have to mention anything about your out of status anywhere. With legal 2nd entry you establish new status.
Your case is not adjustment of status, you reenter the country with new status, 180 days doesn't apply to you.
P.S. this is not a legal advise

Thanks s001. My lawyer was also saying same.