When109Cd is placed in a liquid scintillation counter, 146±1 counts are obtained for every 100109Cd nuclides which undergo decay. Thus, the average efficiency for each of the two steps in the decay process is 73%. In examining the distribution of energy among the windows available, it was noted that the distribution pattern is quite similar to that of14C. An average Cherenkov counting efficiency, in water, was found to be 0.0258±0.0005%. Both 0.010M K2Cr2O7 and CHCl3 quench the count rate, particularly in the lower energy channel, where count rates are suppressed by up to a factor of 20.