The differences in the mean square nuclear charge radius delta (r 2) of the even cadmium isotopes 100<or=A<or=116 have been determined by means of Kalpha 1 X-ray isotopic shift measurements. The results are delta (r2)=0.135+or-0.022 fm2, 0.132+or-0.020 fm2, 0.142+or-0.026 fm2 and 0.42+or-0.02 fm2 for the isotope pairs 110-112, 112-114, 114-116 and 110-116 respectively. These results are in agreement with the available optical isotopic shift (OIS) data. Comparison with the available elastic electron scattering (EES) results shows good agreement for the pairs 112-114 and 114-116, and reasonable agreement for the pairs 110-112 and 110-116.