Its scope covers the taxonomy, nomenclature, identification, characterisation, culture preservation, phylogeny, evolution, and biodiversity of all microorganisms, including prokaryotes, yeasts and yeast-like organisms, protozoa and algae.

[2][3][4] In addition to research papers, the journal also publishes the minutes of meetings of the ICSP and its various subcommittees.

Although several different comprehensive nomenclature systems were invented (most notably, that described in Bergey's Manual of Determinative Bacteriology, first published in 1923), none gained international recognition.

[2][6] For decades, the journal's cover quoted Dutch naturalist Otto Friedrich Müller: "the sure and definite determination (of species of bacteria) requires so much time, so much acumen of eye and judgement, so much of perseverance and patience that there is hardly anything else so difficult.

[2][6][8] Publication moved to the United Kingdom in 1998, the journal being taken over by the Society for General Microbiology, in conjunction with Cambridge University Press.

[6] The journal publishes research papers establishing novel prokaryotic names, which are summarized in a notification list.