The 34 taxa of Korean Campanulaceae, including eight genera, 21 species, eight varieties, and five formae were examined for their external morphology such as roots, stems, leaves, flowers, inflorescences, and capsules, and a new key was suggested. The root was classified into three types; fibrous, rhizomatous, and tap root. The stem habit and branching pattern were divided into three types; it was possible to distinguish Codonopsis, Peracarpa and Wahlenbergia from other genera on the basis of these characters. Leaves were also grouped into several types based on the overall shape, margin, presence or absence of petiole, and leaf arrangement Peracarpa and Wahlenbergia were characterized by the leaf type, Codonopsis by the margin, Wahlenbergia, Adenophora except for sects. Remotiflorae and Platycodon by the absence of petiole, Adenophora sect. Platyphyllae by the leaf arrangement, respectively. The flowers were divided into several types based on the corolla shape, color, lobe, calyx lobe, stamen and carpel. Campanula subsects. Tulipella and Codonopsis except for C. pilosula were characterized by the presence of spots and trichomes on the corolla, Asyneuma by the corolla lobe, Hanabusaya by calyx lobe and stamen, and Platycodon by carpel. Four types of inflorescences such as solitary, head like racemous, paniculous, and racemous were found. Floral discs, appeared only in Adenophora, were grouped into three types; conical, cylindrical (squared, elongated), and short-cylindrical Ratio of style and corolla length was divided into three types such as exerted (Adenophora sect. Platyphyllae), equidistant (Adenophora sect Remotiflorae, A. stricta and A. stricta var. lancifolia), and included (remaining taxa). The capsule was also characterized into three types; indehiscent (Peracarpa), apically loculicidal (Platycodon, Wahlenbergia, Codonopsis), and subbasically valvate (Hanabusaya, Adenophora, Asyneuma, Campanula). Thus, stem habit, morphology of stamen, carpel and corolla lobe, capsule dehiscent type, and presence or absence of floral discs could be used to characterize the genera. Also, presence or absence of petiole, calyx lobe, leaf arrangement, morphology of floral discs presence or absence of spots, trichomes on the corolla, and style length appear to be useful for classification of section, subsection and series in Adenophora and Campanula.