Caribou (Rangifer tarandus) were sampled (1995-96) from a mortality event near the Project Chariot site (NW Alaska), the location of a radiotracer experiment in the 1960’s, and reference sites. Radionuclide levels in muscle and bone and the cause(s) of the mortality were determined due to concerns of local residents. Bone gross alpha mean activity (n = 65) was 130.0 Bq/kg, and varied significantly (< 0.01) from 73.3 to 168.0 Bq/kg among locations. Bone and muscle gross beta mean activity was 510.4 and 9.78 Bq/kg. Bone strontium-90 mean activity (n = 58) was 137.8 Bq/kg. Muscle potassium-40 mean activity (n = 65) was 183.0 Bq/kg, and significantly varied from 76.0 to 104.4 Bq/kg by location. Muscle cesium-137 mean activity (n = 65) was 6.67 Bq/kg, ranged significantly from 0.74 to 15.6 Bq/kg by location, and increased with increasing body condition score. Bone potassium-40 mean activity ranged from 18.9 to 47.4 Bq/kg, and muscle strontium-90 ranged from 8.89 to 20.0 Bq/kg. Radionuclide concentrations were at expected levels and low in some cases as compared to Canadian caribou studies.