The interest in the digital steganography grows together with the rise of amounts of multimedia data exchanged over the Internet. This growth provides steganography with new possibilities and opportunities for data hiding. The information hiding in audio streams is considered especially promising due to audio data popularity and possibilities to hide data within audio signals. There are many data hiding methods. The steganography is used to process audio streams, and the new methods are constantly emerging. These methods have different applications and targets, features and properties. This paper presents the Unified Evaluation System (UES) for evaluation, comparison and classification of audio steganography methods proposed by the authors. UES is a set of calculation principles, which are especially combined for audio steganographic methods. The system’s outcomes provide conclusions in order to determine advantages/disadvantages of the methods and to define the audio steganography methods as the most suitable for each particular case.