Clematis taeguensis Y. N. Lee (Ranunculaceae) was first collected from Beommul-dong, Daegu-si and described by Lee (1982) as endemic to Korea. Morphologically, it resembles C. terniflora DC. var. terniflora, C. terniflora var. mandshurica (Rupr.) Ohwi, and C. brachyura Maxim; thus, it is often misidentified and has therefore not been included in domestic flora or research articles after being published as a new species. It was erroneously considered synonymous with C. serratifolia Rehder in sect. Meclatis. In addition, recurring difficulties have also occurred in recognizing its distribution sites. The present study therefore aimed to resolve the taxonomic controversy concerning C. taeguensis and redefine the taxonomy of this species and identify its distribution patterns using comprehensive external morphology and molecular analysis and confirmatory collections. Unlike other related taxa in sect. Clematis, C. taeguensis lacks a shoot remnant in the winter season and has abaxial and marginal hairs on the sepal, yellow to brown style hairs, and a persistent style is more than 1.9 cm long. It also has a limited distribution in the central (Gangwon: Jungseon, Yeongwol; Chungbuk: Jecheon, Yeongdong) and southern (Gyeongbuk: Daegu, Bonghwa; Gyeongnam: Changnyeong) parts of the Korean Peninsula. Molecular analysis via cpDNA sequencing confirmed that C. taeguensis formed its own group. Hence, C. taeguensis should be regarded as a separate species endemic to South Korea.