The diffusion of implanted chlorine in silicon wafers is studied with neutron activation/accelerator mass spectroscopy (NA/AMS). Depth profiles are obtained from as-implanted and annealed samples. While there is a marked difference between the annealed and as-implanted profiles for the lowest implant dose studied, 1013/cm2, the chlorine from the higher dose implants is virtually immobile. The diffusion of implanted chlorine in silicon is characterized by the apparent absence of indiffusion for the experimental conditions studied. However, outdiffusion is rapid at low concentrations for anneal temperatures of 1100°C and above. This behavior is qualitatively similar to that reported for fluorine in silicon at lower temperatures.