The purpose of this paper is to analyze the patterns of Korean EFL learners’ English pronunciation errors in terms of Korean and English consonant and vowel system, syllable structure, and Korean phonological rules. It also aims to provide a wide range of activities for the effective teaching of English pronunciation in the framework of communicative teaching method. The main results of the study are as follows. First, Korean EFL learners tend to mispronounce the following sounds due to the differences of Korean and English consonant system: voiced stop sounds such as [b, d, g], voiced alveolar and palatal fricative sounds such as [z, ʒ, ʤ], and voiced liquid like [r]. Secondly, they tend to have difficulties both in discriminating and producing the contrasts observed in the tense and lax vowels such as [i] and [I], and [u] and [U], due to the absence of the lax vowels in Korean. Thirdly, Korean EFL learners tend to insert the central high vowel [ɨ] between English consonant clusters, due to the different syllable structure. Fourthly, they also tend to pronounce each syllable at the same length of time, regardless of the number of stressed syllables, which can be attributed to the different rhythm. Finally, the negative transfer of Korean phonological rules, especially nasalization, is responsible for the Koreanized English pronunciation. Based on these results, the study provides a wide range of learner centered, task-based, and meaningful communicative activities for the effective teaching of English pronunciation to Korean EFL learners.