Abstract: Idioms are part and parcel of mastering any language. They are a prominent natural part of our everyday discourse since they reflect cultural and linguistic boundaries enabling communication between different cultures. This paper, therefore, attempts to explore the different types of idiom, shed lights on some Arabic and English idioms and focus on the difficulties faced by learners and translators. Bearing in mind these aims, some Arabic and English idioms were selected and then explained. The overall results showed that idioms can never be translated literally; context, equivalence and semantic relativism should be considered when dealing with idioms. To be communicatively and linguistically competent, translators as well as learners should find the equivalence in the same language first and then in the target language. As a result, it is strongly recommended that translators as well as learners should be fully aware of some translation techniques and the context of the discourse s/he is dealing with.