The author, on the basis of literature and his professional therapeutic experience, describes the meaning of voice signals in diagnosing patients' problems and improving communication during the therapeutic dialogue. In the article, the author also shows the influence of voice features on evoking many non-specific therapeutic factors as well as accelerating the insight and overworking process. The great importance of metasignals, i.e. information concerning emotions hidden in the patient's utterance has been noticed. A therapist is able to recognise them by careful listening to all voice signals, particularly: speech rhythm, vocal height and verbal intensifiers (for example, possibly,,simply,,minimally,,really etc.) The author presents unusual features of voice signals in recognising patients' personalities (especially their parameters such as: domination-submission) as well as patients' involved emotions. Besides this, the author tries to present optimal ways of a therapist's speaking patterns and suitable parameters of a therapist's voice, mainly: speaking pace and rhythm, voice tone and intensity, speech fluency and intonation. In the summary, the author indicates that voice signals themselves may often influence the content of transmission and give a lot of reliable information about patients. Patients' reactions to a therapist's behaviour are highly influenced by the reception and evaluation of his/her voice signals. Therefore, a therapist should analyse voice features present in a therapeutic interaction more thoroughly and become their conscious sender and recipient.