A ubiquitous audio reproducing and servicing method and apparatus for streaming or downloading a lossless audio source from a Content Provider (CP) using a lossy audio source card as an authentication key. The ubiquitous audio reproducing method includes determining whether a memory card storing lossy audio sources and their authentication codes is inserted, if it is determined that the memory card is inserted, transmitting an authentication code of a lossy audio source in the memory card and a system unique Identifier (ID) to a content server by connecting to the content server via a network, and if the content server allows the use of a lossless audio source corresponding to the lossy audio source using the authentication code, streaming or downloading the lossless audio source from the content server.