Stockfish is made by drying various species of fish in the open air to a final water content of 17–18% (w/w). By this treatment the fish acquires a very characteristic flavour. A study was made of the microbiology of blue ling (Molva dypterygia dypterygia) during this process. Aerobic plate counts at 22°C in the flesh of the fish reached a maximum of 4.1 times 107/g dry weight, after drying for 30 days. Analyses of the aerobic/facultatively anaerobic bacterial flora in the flesh showed initially a dominance of Moraxella and Acinetobacter-like spp. As the drying progressed a Gram positive, catalase negative flora appeared, increasing its proportion to 77% of the bacterial content of the fish. Representative strains of these bacteria were identified as Lactobacillus plantarum.