목적: The purpose of the present study was to investigate the formant trajectories of 3 Korean vowels(/i/, /a/, /u/) in nonsense syllables of V/d/V produced by children with bilateral cochlear implants. 방법:Previous studies on formant frequencies were based on average measurement of a given vowel section, which bring up the need for an analysis of dynamic formant movement for articulation. Thus, in this study, acoustical analysis was made at six equidistant time points over the vowel segment. 9 children with bilateral cochlear implants and 9 normally developing children between the ages of 7 and 9 participated in the present study. 결과:The results of the present study were as follows (1) The result showed significant difference in formant trajectory values between two groups. F1 and F2 at each section were significantly higher in the bilateral cochlear implants group than normal group. Over time, F1 trajectory tended to fall, but F2 trajectory showed a tendency to rise. The difference of formant values at each measuring point between groups was greater at the starting point than at the ending point. Furthermore, the F2 trajectory played an important role in distinguishing vowels between groups. (2) The formant trajectories of 3 vowels on F1 by F2 axes showed different aspects between groups. The progression aspect of formant trajectories was more linear in the normal group than bilateral cochlear implants group. (3) The formant trajectories showed reverse directions of progress at some measuring points for vowels /a/ and /u/ in the bilateral cochlear implants group. 결론:From the results, it can be concluded that formant trajectories provide useful and important information in dynamic articulatory gestures of Korean vowels, which may be applicable to speech therapy for cochlear implants.