A complaint where the allegations are sworn to by the plaintiff (or, in limited cases, by the plaintiff's counsel) demonstrating to a court that the charges against the defendant have been investigated and found to be of substance. In federal court, a complaint does not need to be verified unless a rule or statute specifically states otherwise (Federal Rules of Civil Procedure (FRCP) 11(a)).
Examples of rules which may require a verified complaint include:
FRCP 23.1, governing derivative suits.
FRCP 65(b), governing the issuance of a temporary restraining order (www.practicallaw.com/4-502-5116) without notice.
Typically a complaint is verified by attaching a page at the end containing a statement made under oath that:
The plaintiff has reviewed the complaint.
Regarding the allegations of which the plaintiff has personal knowledge, the plaintiff believes them to be true.
Regarding the allegations of which the plaintiff does not have personal knowledge, the plaintiff believes them to be true based on specified information, documents, or both.
The verification page generally also contains a "jurat" block where a notary public or other officer certified to administer oaths certifies that:
The notary identified the plaintiff.
The notary administered an oath to the plaintiff.
The plaintiff signed the affidavit in the notary's presence.
An unsworn verification page can also be used if it cites the language of Title 28, Section 1746 of the US Code.
For information concerning the drafting of a verified complaint, see Standard Document, Complaint (Federal): Drafting Notes: Verification Language Generally (www.practicallaw.com/9-507-9951), Verification Language in Shareholder Derivative Suits (www.practicallaw.com/9-507-9951) and Signing the Verification (www.practicallaw.com/9-507-9951).