Comparisons of the air kerma standards of six national laboratories, c
arried out in Cs-137 gamma radiation, show an overall agreement of 0,8
% between the standards. This result is not quite as good as that of
comparisons in Co-60 gamma radiation, mainly because the evaluation of
the ionization-chamber wall correction is less accurate for Cs-137 ra
diation. However, this agreement is acceptable for radio-protection ap
plications.