The K-electron capture probability (PK) for the 268.7 and 77.3 keV states of 197Au in the decay of 197Hg (64.1h) have been determined from the KX-ray gamma ray summing in a HPGe X-ray detector. The measured values, PK(268.7)=0.746_+0.033 and PK(77.3)=0.774 +0.036 are found to be in good agreement with the theoretical results.