The fifth amendment prohibits the government from compelling a person to give testimony that is self-incriminating. However, the government can compel a person to give potentially self-incriminating evidence by granting that person immunity from prosecution. The current Federal immunity statute details the conditions for a formal grant of immunity, which must be approved by a judge in order to protect the interests of the witness and the government. No such procedural protections apply to an informal grant of immunity, however, and it is not clear if prosecutors have the power to grant informal immunity to a witness. If prosecutors do not have the power to grant informal immunity, then the testimony given by a witness relying on informal immunity could be used against him. The article analyzes the fifth amendment self-incrimination clause as well as case law on immunization of a witness and proposes a Federal statute permitting prosecutors to enter into flexible and informal immunity agreements with witnesses about self-incriminating criminal activity. The proposed statute would provide the constitutional minimum of use and derivative use immunity and would allow for transactional immunity as well as ensure that information obtained through an informal immunity grant could never be used against the provider. 408 footnotes.