Soils and food crops from a former tin mining location in a high background radiation area on the Jos-Plateau, Nigeria were collected and analyzed by gamma spectrometry to measure their contents of 40 K, 238 U and 232 Th. As well as collecting samples, in situ dose rates on farms were measured using a precalibrated survey meter. Activity concentrations determined in food crops were compared with the local food derivatives or diets to investigate the possible removal or addition of radionuclides during food preparation by cooking or other means. Potassium-40 was found to contribute the highest activity in all the food products. The activity concentration of 40 K, 238 U and 232 Th in local prepared diets ranged between 60 and 494Bqkg −1 , between BDL and 48Bqkg −1 and between BDL and 17Bqkg −1 , respectively. The internal effective dose to individuals from the consumption of the food types was estimated on the basis of the measured radionuclide contents in the food crops. It ranged between 0.2μSvy −1 (beans) and 2164μSvy −1 (yam) while the annual external gamma effective dose in the farms due to soil radioactivity ranged between 228μSv and 4065μSv.