It has been known that Korean preschoolers are actively engaged in reading and writing development. The purpose of this study was to examine the extent of Korean children's word reading and word writing abilities by phonological, orthographic, and morpho-semantic abilities. Methods: Seventy 5-to 6-year-old children were participants of this study and their average of IQ score was 100. Each child read and wrote 14 two-syllable words and 14 two-syllable nonsense words and the accuracy was scored at grapheme level. Phonological processing abilities were measured by phonological awareness (PA), rapid automized naming (RAN), phonological memory (PM); whereas letter knowledge (LK) and copying skills were measured for orthographic abilities, and morphological awareness (MA), vocabulary, story grammar recalling for morpho-semantic abilities. Multiple regression analyses were performed with SPSS 23.0. Results: LK, RAN, PM, and MA explained 57.2 percent of word reading while LK, RAN, PM, and copying explained 65.1 percent of nonsense word reading. LK, copying, MA explained 66.7 percent of word writing while copying, PA, and LK explained 59.1 percent of nonsense word writing. Conclusion: Given that RAN and PM explained word and nonsense word reading, and PA explained nonsense word writing, phonological processing abilities seemed to be involved in early literacy actively. Korean children seemed to be in partial to full alphabetic stage before formal elementary education. Most interestingly, the dual-route word reading model differentiating lexical and non-lexical route could be applied to Korean children's early reading development. Further studies are needed to explore early identification of developmental dyslexia from the kindergarten level.