Strictly anaerobic halophiles were isolated from canned Swedish fermented herrings (Surströmming). All isolates were phenotypically uniform with some exceptions and were identified as the genus Haloanaerobium and assigned to either Haloanaerobium praevalens or Haloanaerobiuim alcaliphilum. A comparative analysis of 16S rDNA sequences revealed that the representative strain S-8 of the isolates was identical to that of Haloanaerobium praevalens DSM 2228T. Furthermore, this strain exhibited high levels (> 80%) of DNA-DNA homology with Haloanaerobium praevalens DSM 2228T. This is a novel report of halophilic anaerobes isolated from a food product. Such anaerobes may contribute to the intense flavor and the swollen can characteristics of Swedish fermented herring.