Prime Minister Essam Sharaf left Dar al-Fouad hospital late on Monday after his health condition improved.
Sharaf, 59, suffered from fatigue Monday after holding meetings to choose new members for his ministry.
Sharaf is expected to resume work Tuesday to prepare a final list of nominees for his cabinet after the swearing-in of the new ministers was postponed.
A medical source at the hospital said Sharaf underwent some medical checkups after suffering from fatigue. His condition is stable, the source said.
Sharaf announced the reshuffle to placate protesters demanding deeper political and economic reforms after the 25 January revolution which ousted ex-president Hosni Mubarak.
The protesters, who have camped in Cairo's Tahrir Square since 8 July, have also demanded a quick trial of Mubarak.
They said the reshuffle, which would change half the cabinet, only partially met their demands.
Interior Minister Mansour al-Essawy is set to keep his post. The police, who fall under his ministry, have been targeted by protesters because of tough tactics used during and after the uprising that toppled Mubarak.
