This research note reveals a creole used in Yilan County, Taiwan, which we have named ”Yilan Creole.” Yilan Creole emerged from contact between Atayal and Japanese. Usage of this creole can be observed mainly in 4 villages of Yilan County in Eastern Taiwan. But the existence of Yilan Creole is hardly known to the academic world. This research note first clarifies the sociolinguistic environment of Yilan Creole, including its geographical distribution, current use, and the sociohistorical background. Second, we describe its structural characteristics in phonology, lexicon, and morphosyntax. Since Yilan Creole is not being transmitted to the younger generation and is facing extinction, having a comprehensive description of Yilan Creole is an urgent subject for our future research.