The state-run KUNA news agency reported on Thursday that Sheikh Sabah Al Ahmad Al Sabah left the hospital.
He entered the hospital Wednesday for checks.
Sheikh Sabah has ruled Kuwait since January 2006. He came to power after parliament voted unanimously to oust his predecessor, the ailing Sheikh Saad Al Abdullah Al Sabah, just nine days into his rule and shortly before lawmakers received his formal letter of abdication.
In recent months, he’s been working to try to negotiate an end to the diplomatic crisis engulfing Qatar after four Arab nations cut ties to Doha.
Kuwait is an oil-rich OPEC member wedged between Iraq and Saudi Arabia.