This paper aims to investigate the key lexical areas of difficulty for Australian students of Korean as a foreign language (KFL). Specifically, this study intends to identify the lexical features that present particular difficulties to English native speakers learning Korean; to classify those lexical errors in terms of their type and frequency; and to provide possible explanation for the cause of those lexical problems. The subjects selected in this study are 71 second- and third-year students from three universities. They are native speakers of English or are believed to have English as their first language. The data used in this study come from written examination papers administered at the three universities. 305 lexical errors have been identified for analysis. Among the 11 error categories identified in this study, wrong word choice caused an overwhelmingly high percentage of errors. The study concludes with discussions about theoretical and pedagogical implications.