There are bi-directional links between phonological and lexical development in early language acquisition. This study analyzed phonological characteristics of words which 12-to 30-month-old children produced as recorded by parent reports, as well as early lexicons in Korean version MacArthur-Bates Communicative Development Inventories (K M-B CDI). Methods: The frequency of phonemes and word structures in all the words in the K M-B CDI were analyzed. The K M-B CDI was administrated to parents of 193 children. The groups were divided into the three age groups: 12-17 months, 18-23 months, and 24-30 months. Word lists acquired by 50% to 75% of children in the three age groups were phonemically transcribed and then the frequency of phonemes, consonants types in the initial position, and word structures were analyzed for each age group. Results: The most common word shapes in the K M-B CDI were CVCV and CVC, and were either disyllables or monosyllables. The most common phonemes of words in the K M-B CDI were /l, k, n, a, i/. Seventy-five percent of children aged 12-17 months produced only words with /m/ and /p*/, which start with either a vowel or nasal. The two groups below 24 months produced the VCV words shape most frequently. As children expand their expressive vocabulary with age, the number of phoneme types produced, the percentage of words starting with stops, and the word shape inventory increased. Conclusion: This study showed the phonological characteristics of early lexicon in Korean-acquiring children, which have implications in selecting target words for intervention considering both early phonological and lexical development.