One of the most challenging problems for EFL students is to be able to express themselvesnot just grammatically but also acceptably and naturally in English in appropriate contexts.The ability to produce acceptable and natural expressions in English is closely related to theEFL students' competence in collocation- which words go together in normal usage. Thisstudy therefore investigated Libyan EFL university students' lexical collocation use. It alsoaims to examine how learners' L1 (Arabic) influences their production of collocations. Itanalyzes their problems in the usage of six patterns of lexical collocations: verb+ noun.noun+ verb noun+ noun adjective+ noun verb +adverb adverb+ adjective.Participants of the present study were 185 Libyan university students majoring in English atthe department of English language at Al-Jabal Al-Gharbi University. Data for the study wascollected from a multiple-cho ice test consisted of 60 items and a translation task comprised of28 items alongside a self- responding quest ionnaire. The data were examined and the resultsrevealed that the informants' ability is lower than expected. The findings also showed thatLibyan university students do have problems with English lexical collocations in bothreception and production of all patterns of lex ical collocations.Results also indicated that learners' Ll and their amount of exposure to English had a stronginfluence on the learners' acquisition of English lexical collocations. The findings of thisstudy have some immediate implications for both language learners and teachers ofEFL/ESL as well as for writers of materials.