This review discusses the recent advances in understanding the mechanism by which mTOR regulates autophagy, focusing on mammalian mTOR (mTORC1) and its interaction with the autophagy machinery. mTOR is a serine/threonine protein kinase that plays a central role in regulating cell growth and is inhibited under nutrient starvation conditions, which is crucial for autophagy induction. The activity of mTOR is regulated by nutrient sensing pathways, growth factor signaling, and stress responses. In yeast, the Atg1 complex, which includes Atg1 and its binding partners Atg13, Atg17, Atg29, and Atg31, is a key component in the autophagy pathway. mTOR phosphorylates Atg13, disrupting the complex and inhibiting autophagy. In mammalian cells, the counterpart of Atg1 is the ULK complex, consisting of ULK1 and ULK2, along with their binding partners Atg13, FIP200, and Atg101. mTORC1 phosphorylates ULK1/2 and Atg13, inhibiting their kinase activity under nutrient-rich conditions. Under starvation, mTORC1 is dissociated from the ULK complex, allowing ULK1/2 to take an active conformation and phosphorylate Atg13, FIP200, and itself, triggering autophagosome formation. The review also discusses the crosstalk between ULK complexes and other autophagy machinery, such as the hVps34 complex, Atg5-Atg12 conjugation systems, and Atg4-Atg7-Atg3-Atg8 conjugation systems. The ULK complexes function as a critical node in transmitting nutrient and growth factor signaling to the autophagy machinery via mTORC1, and their regulation by mTORC1 is essential for autophagy induction.This review discusses the recent advances in understanding the mechanism by which mTOR regulates autophagy, focusing on mammalian mTOR (mTORC1) and its interaction with the autophagy machinery. mTOR is a serine/threonine protein kinase that plays a central role in regulating cell growth and is inhibited under nutrient starvation conditions, which is crucial for autophagy induction. The activity of mTOR is regulated by nutrient sensing pathways, growth factor signaling, and stress responses. In yeast, the Atg1 complex, which includes Atg1 and its binding partners Atg13, Atg17, Atg29, and Atg31, is a key component in the autophagy pathway. mTOR phosphorylates Atg13, disrupting the complex and inhibiting autophagy. In mammalian cells, the counterpart of Atg1 is the ULK complex, consisting of ULK1 and ULK2, along with their binding partners Atg13, FIP200, and Atg101. mTORC1 phosphorylates ULK1/2 and Atg13, inhibiting their kinase activity under nutrient-rich conditions. Under starvation, mTORC1 is dissociated from the ULK complex, allowing ULK1/2 to take an active conformation and phosphorylate Atg13, FIP200, and itself, triggering autophagosome formation. The review also discusses the crosstalk between ULK complexes and other autophagy machinery, such as the hVps34 complex, Atg5-Atg12 conjugation systems, and Atg4-Atg7-Atg3-Atg8 conjugation systems. The ULK complexes function as a critical node in transmitting nutrient and growth factor signaling to the autophagy machinery via mTORC1, and their regulation by mTORC1 is essential for autophagy induction.