The focus of the present study is on the semantic aspect of idioms as used in the discourse of British and Latvian newspapers. The central argument is that these language phenomena can be properly encoded and decoded only provided that the textual and situational contexts are taken into consideration. Outside a context most of idioms (especially those with complete transfer of meaning) are non-predictable unless their meanings are known. However, used in discourse and the situational context being taken into account, they often are fully comprehensible and motivated. The paper attempts to account for various uses of idioms in discourse, and it will be illustrated that situational and textual contexts are indispensable factors in the analysis of the figurative meaning of idioms.