The survival, growth and distribution of organisms in hypersaline environments is discussed using cyanophytes (cyanobacteria) as examples. The distinction between halophilic (Na+-requiring) and halotolerant organisms is not adequate to describe the entire spectrum of adaptations to salt. The classical division into stenohaline (narrow) and euryhaline (wide) adaptational types, with optima identified as oligo-, meso- and polyhaline, better reflects both organismal adaptations and the environmental conditions to which these are adjusted and is therefore recommended as a conceptual model.