Objectives: Two distinctive characteristics of late talking children are reduced vocabulary size and delayed phonological skills. Few studies describe the phonological development status of late talking children by considering the Korean speech sound system. This study investigates the phonological development characteristics of 18 to 30-month-old late talking children as compared with typically developing children. Methods: The participants included 19 late talking children and 19 typically developing children. To investigate their phonological developments in more detail, each group was divided into two age groups who were 18-23 months and 24-30 months of age, respectively. Based on their 30-minute spontaneous speech samples, we examined the number of total utterances, number of different words, eojeol structure types, vocalization levels, consonant production ratio, and frequency ratio of consonants based on the place and manner of articulation. Results: Late talking children, as compared to typically developing children, showed fewer number of utterances and expressive vocabularies, lower vocalization levels, fewer number of consonant inventory and eojeol structure types. Regarding consonant types, typically developing children showed diverse speech production from the frontal and posterior parts of oral cavity whereas late talking children showed higher production of frontal sounds. The 24 to 30-month-old late talking children compared with 18 to 23-month-old late talking children displayed significantly higher performances in vocalization levels, palatal affricate sounds and the number of different eojeol structure types. Conclusion: These findings imply that we should examine their limited articulation and phonological abilities as well as the expressive vocabularies in late talking children in order to identify the children who need early speech-language interventions.