The hackers gained entry to Mrs Palin's Yahoo! email account, which she used for official business as Alaska's governor.
They have disclosed as evidence some personal messages she received since being selected by John McCain as the Republican vice-presidential candidate.
Members of Anonymous, an online group known for its attacks against the Church of Scientology, claimed responsibility for the hack, and posted copies of two emails, a contact list and family photos to Wikileaks, a website that hosts leaked documents.
The McCain campaign reacted angrily to the hacking, saying in a statement: "This is a shocking invasion of the governor's privacy and a violation of law.
"The matter has been turned over to the appropriate authorities and we hope that anyone in possession of these e-mails will destroy them."
The disclosure has raised fresh questions about Mrs Palin's use of nongovernment email accounts to conduct state business.
Read The emails HERE