Abstract: The invention relates to a controlled-release formulation for preventing and/or treating sleep disorders comprising Zaleplon or a pharmaceutically acceptable salt thereof in immediate release form and Zolpidem or a pharmaceutically acceptable salt thereof in sustained release form, wherein Zaleplon or a pharmaceutically acceptable salt thereof and Zolpidem or a pharmaceutically acceptable salt thereof are released in two phases where the first phase is a immediate release phase of Zaleplon or a pharmaceutically acceptable salt thereof and the second phase is a sustained release phase of Zolpidem or a pharmaceutically acceptable salt thereof.