Aims: The aim of this work was to investigate the spatial and temporal distribution of species and strains of non-starter lactic acid bacteria (NSLAB) within Cheddar cheese. Methods and Results: Randomly amplified polymorphic DNA was used to identify and track the principle species and strain groups of NSLAB present. The same strains dominated each location examined within a cheese at any particular time point. Temporal change in species and strains of NSLAB during ripening was observed. A mixture of Lactobacillus paracasei, Lact. plantarum, Lact. rhamnosus and unidentified strains was found up to 6 weeks of maturation, thereafter only Lact. paracasei strains were isolated. Conclusions: Little variation in the spatial distribution of NSLAB strains occurs within Cheddar cheese; however, temporal changes in the species and strains were observed during ripening. Significance and Impact of the Study: The complex changes in the composition of the NSLAB community of Cheddar cheese may be the source of the variation in flavour that is seen in commercial practice.