i co-signed on my sisters student loan (who is not paying it of ) . i am unable to pay her loans ,should i file for bankruptcy ?

In most bankruptcy cases student loans are not dischargeable debts.  In some cases, the debtor, or in this case co-debtor, can apply for a hardship with regards to the loan, but these are extremely difficult to obtain.  You should speak with a local bankruptcy attorney, as there may be other options available, or you may qualify for the hardship. Each case is different, and needs to be examined individually. This is not intended to be legal advice, and is general in its nature. No attorney-client relationship exists or is formed by this information. Furthermore, this does not represent the views or opinions of LexisNexis or its affiliated companies.