This paper deals with the representation of idioms in “Explanatory dictionary of the Russian everyday speech” (ed. L.P. Krysin), their lexical-grammar features, the difficulties with which the authors of the dictionary are faced and how they are overcome. The article consists of two parts. In the first part the variants of representation of idioms in the lexical entry, the main principles of attribution of the unit to the zone PHRAS and examples of noting additional stylistic marks are considered in details. The second part is devoted to description of the lexical-grammar features of the colloquial idioms. Their greater dependence on the context (parentheses, dependent words, government, etc.) is mentioned. A lot of attention is paid to the new meanings of some idioms in the colloquial speech. The examples of the idioms, described for the first time in the above-noted dictionary, are given as examples. In conclusion the readers are suggested to estimate some variants of usage of the idioms in the modern colloquial speech. It is concluded about when we can speak of meaning extension in this type of communication and when it is a case of the incorrect usage of idioms.