Key words:explicit knowledge, implicit knowledge, foreign language, language acquisition, interlanguage ABSTRACT It has been pointed out that linguistic knowledge should always be analysed in terms of two different types of knowledge: explicit and implicit. While the access to explicit knowledge is slow and difficult, the access to implicit knowledge is fast and easy. It is, therefore, implicit linguistic knowledge that enables speakers to communicate spontaneously. Because of that it would be ideal if all knowledge of L2 were implicit. However, L2 knowledge is only partly implicit, and usually, especially in a foreign language context, mostly explicit, as a result of different processing underlying the development of L1 and L2 knowledge. The question that arises is which benefits learners have of explicit knowledge, and whether, although different, these two types of linguistic knowledge are interrelated. This article reports on a study which analysed the foreign language learners’ linguistic knowledge in terms of both explicit and implicit knowledge. Implicit knowledge was measured by means of an oral elicited imitation test and explicit knowledge by means of an untimed grammaticality judgement test and a metalinguistic test. All tests were administered to a sample of 206 participants, Bosnian EFL learners. 100 participants were learners completing primary school (aged 14-15), and 106 were learners completing secondary school (aged 18-19).The results indicated that learners' explicit knowledge is a bit, although not significantly, higher than their implicit knowledge. However, the correlation analyses showed that there is a large and significant relationship between these two types of linguistic knowledge.