With the emergence of mass spectrometry in protein science and the availability of complete genome sequences, proteomics has gone through a rapid development. The soil bacterium Bacillus subtilis, as one of the first DNA sequenced species, represents a model for Gram-positive bacteria and its proteome was extensively studied throughout the years. Having the final goal to elucidate how life really functions, one basic requirement is to know the entirety of cellular proteins. This review presents how far we have got in unraveling the proteome of B. subtilis. The application of gel-based and gel-free technologies, the analyses of different subcellular proteome fractions, and the pursuance of various physiological strategies resulted in a coverage of more than one-third of B. subtilis theoretical proteome.