The relative K-electron capture probabilities (P-K) to the 1383.23, 896.98,
618.09, 442.78 and 322.43 keV levels in Ru-99 in the decay of Rh-99 an mea
sured employing the X-gamma internal sum-coincidence technique. The measure
d values P-K(1383.23) = 0.851 +/- 0.066, P-K(896.98) = 0.834 +/- 0.061, P-K
(618.09) = 0.870 +/- 0.01, P-K(442.78) = 0.882 +/- 0.035 and P-K(322.43) =
0.852 +/- 0.061 are found to he in good agreement with the theoretical valu
es. The dependence of P-K On EC transition energy is discussed.