At the moment more advanced approaches to phonetic transcription are required for different speech technology tasks such as TTS or ASR. All subtle differences in phonetic characteristics of sound sequences inside the words and in the word boundaries need more accurate and variable transcription rules. Moreover, there is a need to take into account not only the normal rules of phonetic transcription. it is important to include the information about speech variability in regional and social dialects, popular speech and colloquial variants of the high frequency lexis. In this paper a reliable method for automatic phonetic transcription of Russian text is presented. The system is used for making not only an ideal transcription for the Russian text but also takes into account the complex processes of sound change and variation within the Russian standard pronunciation. Our transcribing system is reliable and could be used not only for the TTS systems but also in ASR tasks that require more flexible approach to phonetic transcription of the text.