A district court may stay a mixed habeas petition to allow a petitioner to present unexhausted claims to the state court. The defendant here filed his federal habeas petition within the one-year statute of limitations under AEDPA, but by the time the district court found that several of his claims were not exhausted, the statute of limitations had run. The Supreme Court held that the district court could properly stay the petition to allow defendant to exhaust his state claims and then return to federal court to proceed on the timely petition.