This paper discusses the importance of listening comprehension in the learning of English as a Second Language (ESL). It is argued that more emphasis needs to be given to the neglected skills of listening comprehension, since most training in oral communication at the secondary and college level focuses on effective speaking. The paper outlines the American Council on Teaching Foreign Languages' (ACTFL) guidelines for listening proficiency for second language acquisition, and reviews research on the relationship between listening comprehension and language learning, auditory identification and discrimination, listening materials, and the testing of listening skills. The importance of the language laboratory in developing listening skills is emphasized, and several teaching methods that can be used to emphasize listening skills are discussed. (Contains 24 references.) (MDM)