Probable values of the mixing ratios of krypton and its isotopes on Venus by the Pioneer Venus large probe neutral mass spectrometer are reported. An upper limit to most of the xenon isotope mixing ratios is also set. Based on a 36Ar mixing ratio of 30 ppm the krypton mixing ratio is probably 47 ppb and its upper limit 69 ppb. The upper limit for Xe is 120 ppb but there is probably considerably less than 40 ppb. Atmospheric krypton and xenon on Venus exceed terrestrial values by factors of 3.5 and no more than 30, much less than the ratios for neon and argon. It appears that the nobel gases on Venus have a large solar component compared to Earth and Mars.