Chinese cordyceps, also known as Dong-Chong-Xia-Cao, is widely recognized as a famous precious tonic herb, and used as traditional Chinese medicine for centuries. It is mainly used for regulating the immune system and improving functions of the lung and kidney, with anti-tumor, anti-inflammatory, and anti-diabetic activities. Due to its rarity and preciousness, a few chemical components are isolated and identified. Moreover, most of them are common chemical components and widely distributed in other natural resources, such as nucleosides, sterols, fatty acids, sugar alcohols, and peptides. Therefore, a large number of active substances of Chinese cordyceps is still unclear. During our search for chemical constituents of Chinese cordyceps, a new thiazole alkaloid, cordythiazole A (1), was isolated and identified. Its structure was elucidated by comprehensive spectroscopic analysis and single-crystal X-ray diffraction analysis. This is the first report of the presence of thiazole alkaloid in Chinese cordyceps, which adds a new class of metabolite of Chinese cordyceps. Furthermore, a putative biosynthesis pathway of cordythiazole A was proposed based on possible biogenic precursor, genes, and literatures. In addition, it showed α-glucosidase inhibitory activity with potency close to that of acarbose. The discovery of cordythiazole A with α-glucosidase inhibitory activity adds a new class of potential anti-diabetes ingredient in Chinese cordyceps.© 2023. The Author(s) under exclusive licence to The Japanese Society of Pharmacognosy.